Carbon is a great molecular glue. Simply take carbon and add water , you have just got life. Well, it is not quite that simple , but water and carbon combo has succeeded to win life , at least on planet earth. This combo has successfully spread his root all over on planet Earth . It is worth considering that what may be death to us , may be life for other beings. Many of researcher and biochemists also speculated that there are several combination of molecule and solvents that may cause life forms too much differs from us that we have never thought about it. Currently we are thinking about only our version of “sweet spot”. Our searches for extra-terrestrial life forms is totally focused on planets similar to others. There are many biochemistries which may exist in such extreme conditions , we have never thought about it like on venus , saturn, jupiter and even in neptune and uranus. It is worth considering that who do their lab work , are a simply carbon based human working in planet earth’s atmospheric conditions . Ammonia has almost same properties that of the water on extreme condition .it is also good solvent . May be it’s possible that water is last possibility for capable of having life forms in extreme environmental condition as on planet Earth.
Even counter intuitive element such as arsenic may be capable of supporting life forms under right conditions . Even on earth some marine algae incorporate arsenic into complex organic molecules such as arsenosugars and arsenobetains. Several other small life forms use arsenic to generate energy and fascilate growth. Chlorine and sulfur are also possible elemental replacement for carbon. Sulfur capable of of forming long again molecules like carbon . Some terrestrial bacteria have already been discovered to survive on sulfur rather than oxygen , by reducing sulfur to hydrogen sulfide . Nitrogen and phosphorus could also form biochemically molecules. Phosphorus is similar to carbon in that it form long again on its own,. ..,continue…
Titanic boa is largest snake ever discovered. They were between 12 and 15 meter or 33 to 49feet in length and weight about 1135kg or 2500lbs with a diameter of 1 meter at the thickest part of the body.
It is believed to have lived approximately 60 to 58 million years ago, in paleocene epoch. It was recently discovered in columbia.
GIGANTOPHIS GARSTINI
Gigantophis Garstini is another prehistoric snake believed to have measured more than 10 meters, larger than any living species of snake. It was the largest snake before the discovery of Titanoboa. Gigantophis lived approximately 40million years ago in Southern Sahara where Egypt and Algeria situated.
A 19th century scandinallian creature rumored to be a mythical dragon like beast. It is often seen the country(SWEDEN) around marshes, caves and large bodies of water. There have been 40plus eyewitness accounts of this creature. Reports have the Lindorms being 10-20 long, with a body as a man’s thigh, black with yellow flammed belly, a mouth full of white shining sharp teeth, large saucer like eyes, and widely body. It behaves like a snake when cornered. It will rear up on It’s tail in a strike on pounce stance, behave in an aggressive and powerful manner and is also very ill tempered. It is difficult to destroy and when successfully killed will emit a foul smelling odor when in final death throes. Lindorms remain on land until too large to move about easily them it takes to the water where it again begins to grow. Although there are many witnesses, there has been no physical evidence of the existence of Lindorms which has led some to believe in “collective hallucinations”. However, due to high rumor of first hand accounts, not to mention the absurdity of collective or group hallucinations, it is more likely to have been a very live creature at one time and perhaps still. It doesn’t likely that 40plus witnesses could describe it unless they have actually seen it. What do you feel ? Tell me leaving your comment
The hype is beginning to invade the cultural landscape like bio-engineered kudzu: the end of the world is a mere three years away.
In late December, 2012, thanks to an unusual celestial alignment — or maybe just the expiration date of the Mayan calendar — our planet will be wracked and ruined. Look on the bright side: you can blow off your estimated tax payments for that year.
Hollywood producers — never ones to miss a silver lining — are hoping to make some hay with Earth’s imminent quietus. A soon-to-be-released film, bearing the inventive title “2012″, will let you see just how visually stunning doomsday can be.
The brouhaha has got some people’s knickers in a knot. Scientists have waded into this sticky chiffon of pseudoscience and hyperbole, and told everyone to cool it. The end is not nigh, guy. After all, the apocalypse is routinely predicted, but always fails to appear.
This isn’t just a reference to the somber forecasts of the Heaven’s Gate crowd, or other dire warnings at the turn of the millennium — forecasts that were wildly inaccurate. No, you have to consider the big picture: There’s been life on this planet for nearly four billion years, and nothing — not asteroids, gamma ray bursts, shifting magnetic poles, or the occasional supernova — nothing has managed to snuff it out. Life’s tougher than a leather sandwich.
The idea that the Mayan calendar could tell you when the world is going to end is straight-out goofy. Heck, if the Mayans were this good at divining the future, you’d think their empire would still be around. As for cosmic alignments — well, they happen all the time, and no one seems the worse for wear. And indeed, what difference could they make? Work it out: even when Jupiter is closest to Earth, the force it exerts on our world is 20 thousand times weaker than that exerted by the Sun every day (and the influence of the other planets is far less than Jupiter’s).
So except for those benighted souls who insist on confounding movies with reality, the whole thing is a tempest in a teacup, right? Isn’t that what all the science types will be writing once the film hits the multiplex?
Of course it is. But there’s also this: doomsday for humans really willhappen, at least if a few hundred million extinct species are any precedent. It’s been estimated that 99.9 percent of all the critters that ever wiggled or waddled across this planet are past tense.
In other words, and despite the fact that we blithely think of ourselves as the crown of creation, we’re no more Nature’s ultimate product than’56 Chevys were the last of the cars. Our species will come to an end, and, presumably, be replaced by a new model.
But not yet. Not in 2012. And the reason is what I call the “why now?” factor, which is really only a temporal version of the Copernican principle. Stated in simple terms, today’s not likely to be a special time.
Here’s an example. Many people are convinced that aliens have come to Earth to abduct humans. But why now? Why is it that, given 10,000 generations of human history, the aliens are bestowing their unwanted attentions on people today? That’s like winning the lottery, even if the prize is not as savory as a pile of cash.
Princeton physicist J. Richard Gott exploited this idea a decade or so ago to gauge everything from cosmic timescales to the run of Broadway plays. A simplified Gott calculation of Homo sapiens’ tenure would go like this: Adopting the “why now?” philosophy, we can say with 98 percent certainty that humankind is neither in the first 1 percent of its existence, nor in its last 99 percent. Doing the arithmetic, that implies our species has something between two thousand years and twenty million years to go.
Those numbers don’t include ruin in 2012.
But of course you might argue that the “why now?” principle doesn’t hold because we’re making today special by wrecking the world. Just about any school kid can rattle off schemes for turning humankind into exhibit fodder for the museums of the future: climate change, nuclear war, pandemics, or just depletion of essential resources.
As bad as these contemporary troubles might be, it’s hard to argue these threats could wipe biology from the face of the Earth.
And in any case, the type of doomsday scenarios examined in films such as “2012″ aren’t destruction at our own hand. They are lugubrious calamities caused by external factors (e.g., pernicious galactic alignments). For such external phenomena, which take scant notice of humans, the “why now?” principle applies.
To think otherwise is merely to assume that the cosmos revolves around us. And that idea was given the boot more than 500 years ago.
With all this frightfulness flying at your ship, you’d want some kind of defense, besides just hoping they’ll miss. As mentioned before, advances in effectiveness of weapon lethality and defensive protection are mainly focused on the targeting problem. That is, the weapons are generally already powerful enough for a one-hit kill. So the room for improvement lies in increasing the probability that the weapon actually hits the target. And the room for improvement on the defensive side is to decrease the probability of a hit. Weapons can be improved two ways: increase the precision of each shot (precision of fire), or keep the same precision but increase the number of shots fired (volume of fire). Precision of fire is governed by [a] the location of the target when the weapons fire arrives, [b] the flight path of the weapons fire given characteristic of the shot and the environment though which the shot passes, and [c] the weapon’s aiming precision. Volume of fire is governed by [d] the weapon’s rate of fire and [e] the lethality of a given shot.
A defense can interfere with the [a] location of the target by evasive maneuvers. There isn’t really a way to interfere with [b] the characteristics of a shot, short of inserting a saboteur into the crew of the firing ship. A defense can interfere with the environment through which the shot passes by such things as jamming the weapon’s homing frequencies or clouds of anti-laser sand (which may work in the Traveller universe, but not in reality). There isn’t really a way to directly interfere with [c] the weapon’s aiming precision(again short of a saboteur), though one can indirectly do so by decreasing the target’s signature, increasing the range or jamming the firing ship’s targeting sensors and degrade their targeting solution.
Finally, while one cannot do much about the [d] weapon’s rate of fire, the [e] lethality of a given shot can be effectively reduced by rendering harmless shots that actually hit. This is done by armor, point defense, and science-fictional force fields.
If the pressurized habitable section of your warship was one single area, a hull breech would depressurize the entire ship (I was going to recount the ancient joke about “why is a virgin like a balloon”, but luckily good sense intervened). A prudent warship design would use air tight bulkheads to divide the interior of the pressurized section into separate areas. This comes under the heading of “not keeping all your eggs in one basket”. The keyword is redundancy.
For the same reason, you’d want back-up life-support systems, power plants, control rooms, and other vital components. And these duplicate systems should be located in widely separated parts of the ship. Otherwise a single lucky enemy weapon shot could take both of them out.Even in the non-pressurized section, bulkheads can help contain destructive effects of hostile weapons fire. So an explosive warhead, with any luck, will merely damage the interior of one compartment, instead of gutting the entire interior of the ship.
Recently a discussion about “armor belts” and the durability of space warships has cropped up by me. This got me thinking about compartments and how they’d be an integral part of a ships survival. Modern naval vessels are divided up into compartments to make them more survivable. Compare a naval frigate to a main battle tank. A tank is basically one compartment. Breach its (very thick) armor and you wreck the tank, since the hit will usually kill the entire crew and/or destroy the internal systems. A frigate however has multiple compartments. Breach the hull of the frigate and while you might wreck one compartment, the entire ship will still float and will often still be able to fight. You have to wreck many compartments, or very specific compartments, in order to mission-kill the ship. It seems to me this vital part of naval design would not be overlooked in space warship design. Beyond the obvious benefits of making it easier to control atmospheric leaks, a space warship built with many compartments that can be isolated would gains a structural benefit in combat.
Now, compartments would be worthless if one hit could completely disable vital systems like life support or command-and-control. Thus all these systems would be distributed all across the ship, with multiple redundancies. Thus if you lose a compartment with life support systems, you have others to fall back on. Having the main CiC compartment destroyed will not totally eliminate your ability to control the ship. This is standard for real world navy ships. Engine systems, command rooms (bridges, CiC’s, etc.) would have secondary locations kept manned in battle in case the main compartments for them are destroyed.
This is also why those compartments would be buried as deep inside the ship as possible. No sense in making things easy for your enemy. True, on modern wet navey warships bridges are still mainly at the highest point of the ship, but that’s mainly to facilitate visual tracking and identification. In space, you cannot see the enemy with the naked eye anyway, so you might as well put your command centers where the enemy has to destroy the entire ship to get at it.
Armor is a shell of strong material encasing and protecting your tinfoil spacecraft. Unfortunately as a general rule, armor is quite massive, so it really cuts into your payload allowance.
Basically, the energy requirement to damage a surface is measured in joules/cm2. If you exceed that value, you do damage, otherwise you fail. Keep in mind that a Joule is the same thing as a watt-second. There are three ways that weapon energy damages a surface: thermal kill, impulse kill, and drilling. Thermal kill destroys a surface by superheating it. Impulse kill destroys a surface by thermal shock. In the calculations for the SDI, the amount to thermal kill a flimsy Soviet missile is about 1 to 10 kilojoules/cm2(100 MJ/m2) deposited over a period of a second. The same energy deposited over a millionth of a second is required for an impulse kill. Since the laser beam tends to be meters wide, the beam energy is in the hundreds of megaJoules.
However, neither thermal kill nor impulse kill works very well with armor. So we use the third method: drilling. The amount of energy required to drill through an object is within a factor of 2 or so of the heat of vaporization of that object. There are also two other limits: the maximum aspect ratio of the hole is usually less than 50:1, and the actual drilling speed, for efficient drilling, is limited to about 1 meter per second (depending on the material).
ThereforeTherefore, the best anti-laser armor will be that material with the highest vaporization energy for its mass. The best candidate is some form of carbon, at 29.6 kilojoules/gram. You do not want a form that is soft or easily powdered, or the vapor action under laser impact will blow out flakes of armor, allowing the laser to penetrate much faster. Steel has a higher vaporization energy, but it masses more as well.
Under laboratory conditions, if an armor layer was 5 g/cm2 of carbon, burning through a 1 cm2(1.12 cm diameter) spot of armor would take about 148 kilojoules and 20 milliseconds. An AV:T laser cannon with 50 megaJoules could burn through 330 such armor layers in a few seconds, under laboratory conditions (i.e., enough layers to burn through the entire ship the long way).
However, under combat conditions there is no way one could focus the laser down that tiny and keep it on the same spot on the target ship for multiple seconds.
It would be better to use a beam focused down to a larger 10 cm2 spot (11.2 cm diameter). Granted the beam power required to penetrate jumps from 148 kilojoules to 15 megaJoules, but now if we have an uncertainty in the target’s velocity of up to 5 meters per second it doesn’t matter.
Of course, if price is no object, you can do better than carbon. Boron has a vaporization energy of 45.3 kilojoules/gram and is only slightly denser than carbon. Expensive, though.
In a 1984 paper on strategic missile defense, it suggested that your average ICBM would require about 10 kilojoules/cm2 to kill it. This would rise to 20 to 30 kilojoules/cm2 with ablative armor, and it would be tripled if the ICBM was spinning on its long axis since the laser couldn’t dwell on the same spot 100% of the time.
As a side note, a Whipple shield is very effective at stopping hypervelocity weapons. With kinetic weapons at closing velocities in excess of 10 km/sec, you’re getting into the realm where armor is less important than blow-through. For armor, you want something that will resist being turned into a plasma for as long as is possible, followed by gaps made of vacuum to make it a Whipple shield.
In science fiction movies and television, we have never really seen all of these features at once. Ironically Star Trek managed to get the distributed systems part correct, we eventually even saw that Federation starships had “battle bridges” to provide emergency control should the main bridge be damaged. But Star Trek has utterly failed to put the bridge in defended positions, or show proper compartments in their designs (As David Gerrold noted, that silly bridge perched on the saucer top of the Starship Enterprise would have been shot off a long time ago). Apparently they rely on their handwavium deflector shields to do the job, which is great until you run out of power. Battlestar Galactica came pretty close, though. The ships systems are distributed, the ship itself compartmentalized, and it has a bridge buried deep in the hull. We just never see redundant engine rooms or command centers, which is probably more of a failing of the script writers than of design. In novels we see this idea used properly, though. The Honorverse novels showcase the benefits of compartmentalization in a very obvious and graphic form, in nearly every novel.
The glow of methane has been detected in the atmosphere of Jupiter-sized alien planet orbiting close to its parent star.
Because the signature of glowing methane, which might be triggered in a similar way to Earth’s auroras, is so strong, it could help scientists better understand the atmospheres of exoplanets, if it turns out to be a common feature among them.
The detection was also made from a ground-based telescope and not space-based one, suggesting that many more detailed measurements of exoplanet atmospheres will be made in the coming years, possibly even the signatures of biological activity, researchers said.
Methane is belched out by certain kinds of microbes on Earth (as well as by big animals, such as cows), and scientists think this is one form that potential alien life could take. (Methane is also created through geophysical and chemical processes on Earth that have nothing to do with life.)
“That’s not where we are today, but that’s where we’re going,” said Mark Swain of NASA’s Jet Propulsion Laboratory in Pasadena, Calif., who led the team that made the methane discovery.
Glowing methane
Scientists detected this particular signature of methane in the atmosphere of an extrasolar planet dubbed HD 189733b, which was one of the first exoplanets to have its atmosphere “sniffed” my spectrometers, which measure the range of light given off by a particular object and show the light signatures that are peculiar to different elements and molecules.
Water vapor, carbon dioxide, and methane have already been detected in HD 189733b’s atmosphere, though that first methane detection had a different signature than the new one.
The new detection seems to be from the fluorescence of methane in the atmosphere of the planet. (An Earth analogue to this phenomenon would be something like the aurora borealis, Swain said.)
The finding, detailed in the Feb. 4 issue of the journal Nature, was unexpected if not a total surprise, as similar signatures have been seen in the atmospheres of bodies in our own solar system.
“It’s not particularly surprising since we have seen fluorescent methane in Jupiter, Saturn and even Titan,” said Seth Redfield of Wesleyan University in Middletown, Conn., who was not involved with the finding, but has previously made detections of sodium in the same exoplanet’s atmosphere. Redfield wrote an opinion article about the new discovery in the same issue of Nature.
Understanding atmospheres
For the atmospheric signatures collected for exoplanets so far, astronomers have assumed that heat is what is causing the emission of various atmospheric constituents, as most are so-called hot Jupiters, which orbit very close to their stars and are bathed in large amounts of stellar radiation.
But heat can’t explain the fluorescence of methane. “The light is being generated by something other than heat,” Swain told SPACE.com.
But the energy source driving the emission is still a mystery.
“We don’t know the answer for that today,” Swain said, but he added that two possible sources where collisions with photons or charged particles from the stellar wind. The solar wind from our sun is not known to cause methane fluorescence in any planets in our solar system.
But the fluorescence does tell astronomers something about the atmosphere of the planet: that the part where the fluorescence is happening is likely “very tenuous layers in the atmosphere of the planet,” Swain said.
This is because fluorescence is what in physics is called a non-locally thermodynamic equilibrium process.
So in an atmosphere that is in locally thermodynamic equilibrium, energy moves between particles primarily through collisions – this can happen because the atmosphere is thick and the molecules are relatively close together. This is the case in the lower portions of Earth’s atmosphere.
But when the atmosphere thins out, its molecules can become far enough apart that the time between collisions is long enough that energy can get to molecules through other means. A similar process occurs in the upper portions of Earth’s atmosphere, where things like the solar wind can collide with particles — this is what creates the auroras that flash over Earth’s poles.
So it’s possible that the signature of methane fluorescence from HD 189733b is coming from a different part of the atmosphere than the previous methane signature, though Swain cautions that it will take more observations and new atmospheric models to really characterize the exoplanet’s atmosphere.
Future detections
Swain and his team are already at work looking for this fluorescent signature in other exoplanets. If it turns out to be a common feature, “it could change how detectable these exoplanets are,” because the signature is strong and unique, Swain said.
Redfield said the finding is exciting because it adds to the list of known exoplanet atmospheric components, which are building up at a time when “we’re just getting use to finding exoplanets.” In a decade, exoplanet atmosphere detections will likely be as routine as exoplanet detections now are, he said.
Making more detections of methane in particular could be helpful because it can be a by-product of biological processes. Building a better understanding of what kinds of methane are out there and where in exoplanet atmospheres the gas occurs could help scientists determine which signatures are most likely to be related to alien biology.
“This is one step on a much longer journey,” Redfield said.
The finding is also exciting, both Swain and Redfield said, because it was made with a relatively modest-sized ground-based telescope, NASA’s Infrared Telescope Facility (IRTF) in Hawaii, whereas most other atmospheric detections were made with space-based telescopes, such as Hubble and the Spitzer Space Telescope.
The detections of atmospheres from the Earth’s surface can only be made in particular wavelengths of light that aren’t absorbed or scattered by the Earth’s atmosphere, but ground-based detections are an important complement to space-based ones because ground-based telescopes are much bigger — while Hubble is 2.4-m telescope, the Keck telescopes (also in Hawaii) are 10 meters in diameter. This means that atmospheres could be observed with more detail or at fainter objects.
This capability “is going to prove really, really critical to understanding these exoplanet atmospheres,” Redfield said.
Swain already has plans to use some bigger Earth-based telescopes in the future.
The age of the Universe has been a subject of religious, mythological and scientific importance. On the scientific side, Sir Isaac Newton’s guess for the age of the Universe was only a few thousand years. Einstein, the developer of the General Theory of Relativity, preferred to believe that the Universe was ageless and eternal. However, in 1929, observational evidence proved his fantasy was not to be fulfilled by Nature.
A very massive, very old cluster of galaxies,
as photographed by the Hubble Space Telescope
In order to understand this evidence, let’s think about how a train sounds to a person standing on the platform. An arriving train makes a noise that starts low and gets higher pitched as the train approaches the listener, sounding like oooooohEEEEEEEE. A departing train makes a noise that gets lower pitched as the train goes away from the listener, sounding like EEEEEEEEoooooooh. This change in the sound of the pitch of the train noise depending on whether it is arriving or departing the listener is called the Doppler shift. The Doppler shift happens with light as well as with sound. A source of light that is approaching the viewer will seem to the viewer to have a higher frequency than a source of light that is receding from that viewer. In 1929, observations of distant galaxies showed that the light from those galaxies behaved as if they were going away from us. If all the distant galaxies are all receding from us on the average, that means that the Universe as a whole could be expanding. It could be blowing up like a balloon. If the Universe is expanding, then what did it expand from? This is what tells us that the Universe probably does have a finite age, it probably is not eternal and ageless as Einstein wanted to believe. But then, okay, how old is the Universe? We know from studies of radioactivity of the Earth and Sun that our solar system probably formed about 4.5 billions years ago, which means that the Universe must be at least twice that old, because before our solar system formed, our Milky Way galaxy had to form, and that probably took several billions years by itself. It would be reasonable to guess that the Universe is at least twice as old as our Sun and Earth. However, we can’t do radioactive dating on distant stars and galaxies. The best we can do is balance a lot of different measurements of the brightness and distance of stars and the red shifting of their light to come up with some ballpark figure. The oldest star clusters whose age we can estimate are about 12 to 15 billions years old. So it seems safe to estimate that the age of the Universe is at least 15 billion years old, but probably not more than 20 billion years old. This matter is far from being settled by astrophysicists and cosmologists, so stay tuned. There could be radical new developments in the future.
“God created man in His own image.” OK, but what about all the other intelligent, cosmic inhabitants? Well, Hollywood has taken care of that. It has created aliens in man’s image.
It’s hardly a major revelation to point out that most movie aliens bear a strong likeness to humans. Typically, they have well defined heads, and two of everything else of note: eyes, nostrils, arms and ambulating legs. They’re strongly anthropomorphic, and if some of these hairless little louts moved into your neighborhood, you’d probably get around to inviting them to dinner.
Aliens that resemble us are convenient for storytelling, because you already know how to read their intentions. Their behavioral cues are familiar, and you can tell if their game plan is to be amorous or aggressive. (In most movies, these are their only options.)
But is there reason to think that actual aliens, from a star system a thousand light-years away, would be similar in appearance to the evolved apes that we now call Homo sapiens? They could be somewhat looks like octopus as shown in picture or may invisible plasma based and so on… Some scientists, such as Cambridge University paleontologist Simon Conway Morris, think there is. After all, there’s a phenomenon in nature known as convergent evolution. It’s the tendency of evolutionary processes to find similar solutions to any given environmental challenge. For instance, if you’re a predator whose existence depends on catching lunch day after day, you probably have two eyes with overlapping fields of view. Stereo vision is a real plus for pouncing on prey.
Similarly, for marine creatures that have a need for speed, the laws of hydrodynamics favor being long, thin, and oh-so-streamlined. Convergent evolution has ensured that barracudas are shaped like dolphins, even though the former are fish and the latter are mammals. Being built like a torpedo just works better.
This mechanism is often invoked by sci-fi writers as a convenient explanation for why so many of their alien protagonists resemble earthlings brushed with battery acid. (Even the language – “convergent evolution” – which is so ponderously Latinate, bespeaks academic merit and scientific plausibility.)
As a consequence, it’s possible that a hominid shape is the best body plan for sentient beings on any world, and no doubt Tinseltown would be pleased to learn that its rubber-suit aliens are good approximations to the real thing. But I’ll bet you dollars to Devil Dogs that any extraterrestrials we detect won’t be muscular guys with deep voices and corrugated foreheads, or even big-eyed, hairless grays. And that’s not because such creatures couldn’t exist. Rather, it’s because of the timescale for non-biological evolution.
Here’s the deal: it’s widely believed that aliens are out there. But proof requires the following: Either aliens need to visit Earth (don’t start!) or we need to detect them with our telescopes – for example, in one of our SETI experiments. In either case, we’re dealing with beings whose technological level is beyond ours. That should be obvious because, after all, we’re not yet at the point where we can engage in interstellar travel. And as for getting in touch via signals, well we’re not blasting continuous, powerful transmissions to lots and lots of other worlds. We don’t have either the money or the equipment. Maybe someday.
In fact, no matter how we find them – in the backyard, on the radio, or through our telescopes – any detected aliens will be at least a century beyond us. More likely, a millennium or more.
OK. But if they’re beyond our technical level, what can we say about their appearance? Well, using our own experience as a guide, consider a human development that seems likely to take place sometime in the 21st century: we’ll invent machine intelligence. Some futurists figure this dismaying development will take place before 2050. Maybe it will take twice that long. It doesn’t matter. By 2100, our descendants will note that this was the century in which we spawned our successors.
So here’s the point: Since any aliens we detect are ahead of us, they’ve already done this; they’ve made the transition from biological to engineered intelligence, and left behind the quaint paradigm of spongy brains sloshing in salt water.
In other words, and despite what “The X-Files” would have you believe, the sort of humanoid, fleshy aliens that routinely populate fiction are very unlikely to be the type we will discover. Instead, they’ll be machines. Dollars to Devil Dogs.
All of which reminds me: the next time your neighbor claims that extraterrestrials have once again hauled him out of his bedroom for distasteful experiments, ask whether the abductor was a protoplasmic being with four limbs, or some sort of complex hardware. I think I already know what the answer will be, and it’s the wrong one.
The video above have good speculations, however nerds are not facts. So many alien species but I think real one would be radically different.
Yet if and when humans do meet creatures from other worlds, they’ll be unimaginably more far-out than anything Hollywood can dream up, Cameron said.
“It’ll be much beyond what we can imagine,” said Cameron, whose “Avatar” opened big last weekend with US$232 million worldwide. “There are creatures right on Earth that are absolutely amazing, and all the aliens are already here, if you look at a small-enough scale or you look under the ocean.”
“Avatar” tells the story of a human, Jake Sully (Sam Worthington), who takes on the form of the Na’vi, 10-foot-tall blue creatures that are the dominant species on the distant moon Pandora. Jake goes native, becoming a warrior in a Na’vi clan and falling for Na’vi huntress Neytiri (Zoe Saldana).
With pointed ears, huge eyes and tails, the Na’vi are anything but human. Yet like most extraterrestrials created by Hollywood, they still have a general humanoid form — two eyes, ears, arms and legs, a nose and mouth, smiles, grimaces and facial expressions we all can recognize.
“We looked at designs for the Na’vi that initially were much more alien,” Cameron said. “When we would draw Neytiri and she had fins on her back and gills and all kinds of weird protuberances and so on in odd places, the question was, well, would you want to do her? No? OK, let’s back off from that. . . . We just didn’t want to take it so far that she had kind of a fish mouth or anything.”
Along with blue skin and tails, the alienness of the Na’vi was conveyed largely through differences in scale. They tower over humans but have delicate proportions, thin frames and limbs, but eyes about twice as wide as ours.
Still, the Na’vi look human enough that audiences can relate to them the way they relate to other characters on screen. Cameron has an explanation for why the Pandora natives bear similarities to humans, which he plans to share down the road.
“We were doing a science fantasy, not true science fiction. We’re not really predicting that there will be humanoids” on other planets, Cameron said. “When I write the novel of ‘Avatar,’ which I’m going to do as soon as the dust clears on the film release, I’m going to deal with the issue of why they look so much like us. Because there needs to be an overarching explanation of that, which I have.”
“Avatar” presents a wild ecosystem in which the Na’vi commune with other animals and even plant life by tendrils that form a mental link. Pandora features giant plants that suck themselves into the ground when threatened, six-legged beasts of burden called direhorses, flying reptilian banshees and tiny jellyfish-like spores that float about the jungle landscape.
A seasoned diver with a passion for the life aquatic, Cameron explored the rich diversity of deep-ocean species in his documentary “Aliens of the Deep.”
Cameron and his design team borrowed ideas from some of the most striking species on our world to augment the fantastic look of the lifeforms on Pandora — bioluminescent dot patterns on the skin of the Na’vi or elaborate designs inspired by tropical fish and frogs on the hides of the banshees.
“I wanted there to be a real exoticism. It was what I had sort of hoped they would do in ‘Jurassic Park,’ not make dinosaurs just kind of like we imagine dinosaurs, but make dinosaurs the way they might have been, which is like purple and gold.
Because there are some lizards and amphibians and fish on this planet, granted on a smaller scale, that are absolutely stunning in their colour patterns.
“So maybe it’s just an overall kind of reverence and sense of wonder for nature and its inventiveness, and that really imbued every decision we made in terms of the creature design.”
What’s alien also comes down to who’s doing the talking. In Cameron’s “Aliens,” the story was told from the perspective of Sigourney Weaver as she joins human Marines in a death match with savage alien predators.
Weaver battled hostile otherworldly monsters in four “Alien” movies, but this time, the tables are turned. Cameron reunites with Weaver on “Avatar,” casting her as a scientist whose fellow humans wage war on the Na’vi to obtain an energy-rich mineral found on Pandora.
Artificial Intelligence is impossible because computers will never be able to think and behave in the same way as human beings.
Artificial intelligence (AI) is a young interdisciplinary field of research that combines cognitive science and computer sciences. A good general definition of its aims was made by Professor Aaron Sloman in Computers and Thought (1989, MIT Press): “AI is a very general investigation of the nature of intelligence and the principles and mechanisms required for understanding or replicating it.” This essay aims to make a critical analysis of the title, taking into consideration any relevant views held by experts in the AI field. It also aims to illustrate some of the major philosophical stumbling blocks that occur in the arguments.
AI is a field of research that has captured the public eye. If AI were possible to the standard of human intelligence it would have a massive impact on our society and lives in general. Consider that at present automation is limited to repetitive, mundane tasks and this alone has slashed the number of jobs in industry. Then consider the advent of automated systems which have intelligence: they could be used in literally any niche of presently human-based employment. Some of the issues AI raises open a “Pandora’s box” of controversial arguments, similar to those raised by genetic engineering. For example, is it right for us to attempt to ‘play God’ and create intelligence? If we are able to create an artificially conscious ‘being’, independent of any ‘divine intervention’, what does this infer about the religious issue of Divine intervention in the creation of human consciousness? It is no surprise that the public is tending to avoid the issue by denying its validity point blank.
Ray Kurzweil and singularity institute are having great effort to create self aware cognitive artificial intelligence but would it be ever possible to create such sort of thingy? He suggests so is possible but when it passes through the organic mind, it ignores the possiblity of artificial intelligence with artificial emotions as It’s nature. Of course, we can create real AI only and only if we have knowledge how really brain function. If we would have real working simulation of brain or say just we know how robust brain is? Then we can think of building a prosthetic brain of silicon running with the power of your provided electricity and might even be solar powered. Actually brain function is more mystic than anything could be scientific. We haven’t recognised the real functioning of brain yet. Do we have? Perhaps, not. But wait, you can’t say that you couldn’t make a prosthetic brain at least as intelligent as a natural bug. You can ignore the technology of which we are owner of. We have technology that could create immature intelligence as what similar to a bug. Can you imagine? Well, It’s time to analyse the level of intelligence what a bug typicaly have. A bug could think: 1. How to take food and manage their food.
2. How to save them? Or say intelligence enough to protect them from hunters.
3. They could detect their prey and they could hunt by attacking on them.
4. They can distinguish between prey and hunter.
5. They can remember their path and can retrieve their track and home.
6. They know how to behave with others.
Oh, I have left one more implication to AI and that is bugs are naturally programmed or say it[somehow they know and avoid eating poisonous plants and prey] has already been encoded in their genomes.
So, is it harder even to enter in first step to create self aware and at least human like intelligence? We have microchips and super fast processors but can they withstand against neurons of bugs?
Computer hardware does have some significant advantages over biological nervous tissue: these advantages indirectly aid the development of AI. The following points are paraphrased from Roger Penrose in his essay “Setting the scene: the Claim and Issues” from the volume “The Simulation of Human Intelligence” (1993, Blackwell). Firstly, Electronic circuits are already about a million times faster than speed of a nerve cell transmitting an impulse. Secondly, electronic circuits have an immense advantage over brains in terms of precision in timing, and accuracy of action. One major pitfall is that no neural network yet constructed has anywhere near the multitude of synapses (ie connections between neurones) that occur in a biological brain, but this may be overcome in time. Moravec H., in his book “mind children” (1988) makes a very valid point in support of the capability of computer hardware for use in AI. He reminds us that the rate of development of computer technology has been accelerating for the past half century: what basis have sceptics in saying that this rate will drop suddenly?
On the other hand, it must be said that biological nerve tissue (ie the material that makes up the human brain) has advantages over computer hardware, namely the capacity for major error tolerance. This applies in terms of both physical and processing capabilities. If a human brain is damaged it will carry on functioning to the best of its ability- this cannot be said for computer hardware at present. If a problem develops in the coding of a computer’s program, it will either ‘crash’ or output ‘gobbledegook’: the human mind is very error tolerant. Some important advances have been made recently in developing computer hardware and software with capabilities nearer to those of a biological brain and ‘mind’, namely heuristics, neural networks: “models of the logical properties of interconnected nerve cells” (quote from Garnham A.’s Introduction to Artificial Intelligence, 1988) and fuzzy logic.
This discussion about computer hardware leads onto the question raised by Sloman A. in “Computers and Thought” of whether the human mind is purely a symbol manipulator. Computers are purely symbol manipulators, so if the human mind is too then this significantly increases the ease of simulating it on computers. However, there may be other operations the human brain is capable of: for example, non-symbolic operations (possibly emotions) or operations that occur below the level of conventional symbol processing (possibly seeing and distinguishing objects).
The crux of the problem in dealing with issues of artificial intelligence is the definition of the word ‘intelligent’. Obviously, the definition provided by a conventional dictionary is not enough because it would be too vague and non-technical. In “Computers and Thought” Sloman states three key features of intelligence: Intentionality, Flexibility and Productive Laziness. On their own these labels are fairly meaningless, definitions are required. (The definitions below are adapted from those given by Sloman in Computers & Thought)
Sloman states that intensionality is “the ability to have internal states that refer to or are about entities or situations more or less remote in space or time, or even non-existent or wholly abstract things.” this definition includes thoughts or desires about the mind in question’s own state, ie various forms of self-consciousness.
Flexibility is the variety of things intentional states can refer to, for instance the variety of types of goals, objects, problems, plans, actions, environments etc, with which an individual can cope, including the ability to deal with new situations using old resources combined and transformed in new ways.
Productive laziness involves avoiding unnecessary work. In the real world almost every task involves so many choices from so many options that to solve a task by enumerating all the possible actions and outcomes would be extremely wasteful of processing time and power. Lazy shortcuts are required, for example testing partial combinations of options to see whether they can possibly be extended to reach the goal of the task- if not they can be rejected at once. Being lazy in this way is usually intellectually harder, yet faster- and speed of processing (or ‘thought’) in the real world is essential for survival.
Sloman’s “three key features” explained here do seem to make a good summary of some of the prerequisites of intelligence, but he makes mention only of “self-consciousness” rather than consciousness itself. The difference between the two terms is important. Self-consciousness is awareness of one’s internal states, and memory of the internal states which have previously occurred; whereas consciousness is a much broader term. Sloman makes no comment on the issue of whether consciousness is required for intelligence- in doing so he avoids enter the lengthy debate. An outline of this debate is attempted to be made in the following paragraph.
To tackle the issue of consciousness, a technical definition is required- something that AI researchers have been arguing over for quite some time. Even now there are in fact many variations of opinions. For sake of conciseness only two will be considered in this essay. Aleksander (professor of neural systems engineering at imperial college, London) refers to the Chambers 20th Century English Dictionary in giving his opinion of the definition of consciousness: “The Waking State of the mind; the knowledge the mind has of anything”. Aleksander postulates a number of attributes for the “waking state” of the mind: learning, language, planning, attention and inner perception. Searle, on the other hand, argues that consciousness is a natural biological phenomenon that occurs because the brain is not a digital computer but a “specific biological organ”. This is an anti-AI point of view. In other words it states that a simulation of a biological brain is only as ‘real’ as a simulation of a liver or kidney. Penrose (in his previously mentioned essay “setting the scene: The Claim and Issues) makes some important comments about this ‘only simulation’ argument:
“If all the external manifestations of a conscious brain can indeed be simulated entirely computationally then there would be a case for accepting that its internal manifestations- consciousness itself- are also present in association with such a simulation” note that Penrose states that this ‘operational argument’ is not entirely conclusive, yet it does have some considerable force.
Philip Johnson-Laird makes an interesting comment on the terminology of the word ‘consciousness’ in his book “The computer and the Mind”.When riding a bicycle you do not think “I must turn the handle bars so that the curvature of my trajectory is proportional to the angle of my unbalance divided by the square of my speed” these computations are carried out unconsciously. According to the argument ‘intelligence must involve consciousness’ then the process of a human riding a bike is not intelligent, instead the intelligent part includes the way in which the method of bike riding was learnt, together with Sloman’s three key features as previously described (Intensionality, Productive Laziness & Flexibility).
The discussion on consciousness here illustrates a major philosophical stumbling block, but it leads away from the thrust of the statement made in the title. The point made here is that consciousness is not necessarily required for all types of intelligence- it is a term that comprises many different interrelated components and levels. Now the question arises as to whether we can quantify the importance of the different constituents of intelligence. It seems that its constituents are not static and their importance vary according to the task in hand.
The view held in the title of this essay is common amongst lay-people. At present there is no conclusive evidence that an AI system will or will not be capable of reaching a level of intelligence parallel to that of human thought and behaviour: so the view held in the title is not entirely invalid. The one important point that the statement misses is that an AI system is any system that exhibits some form or aspect of intelligence. This has already been achieved in systems carrying out tasks such as reasoning, learning, planning and other functions- all of which are accepted as aspects of intelligence. In this respect, the title can be seen as an incorrect and naive statement.
After six years of unprecedented exploration of the Red Planet, NASA’s Mars Exploration Rover Spirit no longer will be a fully mobile robot. NASA has designated the once-roving scientific explorer a stationary science platform after efforts during the past several months to free it from a sand trap have been unsuccessful.
The venerable robot’s primary task in the next few weeks will be to position itself to combat the severe Martian winter. If Spirit survives, it will continue conducting significant new science from its final location. The rover’s mission could continue for several months to years.
“Spirit is not dead; it has just entered another phase of its long life,” said Doug McCuistion, director of the Mars Exploration Program at NASA Headquarters in Washington. “We told the world last year that attempts to set the beloved robot free may not be successful. It looks like Spirit’s current location on Mars will be its final resting place.”
Ten months ago, as Spirit was driving south beside the western edge of a low plateau called Home Plate, its wheels broke through a crusty surface and churned into soft sand hidden underneath.
After Spirit became embedded, the rover team crafted plans for trying to get the six-wheeled vehicle free using its five functioning wheels – the sixth wheel quit working in 2006, limiting Spirit’s mobility. The planning included experiments with a test rover in a sandbox at NASA’s Jet Propulsion Laboratory in Pasadena, Calif., plus analysis, modeling and reviews. In November, another wheel quit working, making a difficult situation even worse.
Recent drives have yielded the best results since Spirit became embedded. However, the coming winter mandates a change in strategy. It is mid-autumn at the solar-powered robot’s home on Mars. Winter will begin in May. Solar energy is declining and expected to become insufficient to power further driving by mid-February. The rover team plans to use those remaining potential drives for improving the rover’s tilt. Spirit currently tilts slightly toward the south. The winter sun stays in the northern sky, so decreasing the southward tilt would boost the amount of sunshine on the rover’s solar panels.
“We need to lift the rear of the rover, or the left side of the rover, or both,” said Ashley Stroupe, a rover driver at JPL. “Lifting the rear wheels out of their ruts by driving backward and slightly uphill will help. If necessary, we can try to lower the front right of the rover by attempting to drop the right-front wheel into a rut or dig it into a hole.”
At its current angle, Spirit probably would not have enough power to keep communicating with Earth through the Martian winter. Even a few degrees of improvement in tilt might make enough difference to enable communication every few days.
“Getting through the winter will all come down to temperature and how cold the rover electronics will get,” said John Callas, project manager at JPL for Spirit and its twin rover, Opportunity. “Every bit of energy produced by Spirit’s solar arrays will go into keeping the rover’s critical electronics warm, either by having the electronics on or by turning on essential heaters.”
Even in a stationary state, Spirit continues scientific research.
“There’s a class of science we can do only with a stationary vehicle that we had put off during the years of driving,” said Steve Squyres, a researcher at Cornell University and principal investigator for Spirit and Opportunity. “Degraded mobility does not mean the mission ends abruptly. Instead, it lets us transition to stationary science.”
One stationary experiment Spirit has begun studies tiny wobbles in the rotation of Mars to gain insight about the planet’s core. This requires months of radio-tracking the motion of a point on the surface of Mars to calculate long-term motion with an accuracy of a few inches.
“If the final scientific feather in Spirit’s cap is determining whether the core of Mars is liquid or solid, that would be wonderful — it’s so different from the other knowledge we’ve gained from Spirit,” said Squyres.
Tools on Spirit’s robotic arm can study variations in the composition of nearby soil, which has been affected by water. Stationary science also includes watching how wind moves soil particles and monitoring the Martian atmosphere.
Spirit and Opportunity landed on Mars in January 2004. They have been exploring for six years, far surpassing their original 90-day mission. Opportunity currently is driving toward a large crater called Endeavor and continues to make scientific discoveries. It has driven approximately 12 miles and returned more than 133,000 images.
Our future, the future of the planet, is cloudy, shrouded in numerous dilemmas, many of which threaten the continued existence of Earth civilization and perhaps Earth life itself. Can our precarious condition persist indefinitely? What is the longevity of a technologically competent civilization?
We stress that the problems facing civilization today are not similar, not even in principle, to those of previous generations. The recent exponential advance of technological achievements and the inability of much of society to cope with them have led to global problems basically different from those confronting earlier peoples on Earth. In no other time of recorded history have humans commanded the means to affect the status of large segments of life on our planet. In one way or another, it’s not inconceivable that the entire planet could be rendered lifeless in the near future.
Examined from afar, the whole predicament before us seems paradoxical. Evolution of matter is responsible for our Galaxy, Sun, planet, and life. And evolution of life is responsible for our intelligence, culture, and technology. But now this very same phenomenon—change—seems to be threatening us. Change has caused many of our present problems, yet to circumvent those problems we need more change. The cause of it all is that humanity is in the process of sliding into the driver’s seat; we have indeed become agents of change. Humans now affect change more rapidly than Nature ever could have.
In the past century, we have increased our speed of communication by more than a million times, our speed of travel a hundred times, and our energy consumption a thousand times. Within the past couple of decades alone, we’ve enhanced by several million times the speed of data processing and the efficiency of weapons development.
Some people, unable to cope with rapid change, argue that technology is the main cause of many of today’s troubles. Exponential population growth, environmental pollution, depletion of natural resources, shortages of food and energy, threats of nuclear incineration, the potential for genetic degeneration, and a host of other ills are now, or soon will be, threatening the viability of Earth civilization and quite possibly all of Earth life itself. Some of these problems are in fact by-products of technology. Yet the saddest problem of all is that our social and political organizations seem unprepared to provide the innovative, foresighted responses needed for our continued existence.
For better or worse, our civilization is fast approaching finite natural limits. A fundamental change in the way things change is now upon us—at least for human life on Earth. This doesn’t necessarily mean an end to civilization. But we are doubtless approaching a finale for the rapid changes we’ve self-inflicted. We cannot communicate faster than light velocity, a speed already achieved by radios and televisions. We cannot travel around the Earth faster than orbital velocity, an ability already attained by space probes and astronauts. We cannot solve the population glut by copping out into space. We cannot consume fuel to the point of thermally polluting the air and melting the polar ice caps. And when it comes to weapons manufacture, we cannot be deader than dead!
Our civilization is now in transition, the likes and scope of which no Earth society has ever before encountered. What are we to do? There are only a few options.
First, our fast-paced society can fail to solve any one of the global problems soon to face us, in which case, for all practical purposes, civilization does go down the tube and perhaps human life becomes extinct. This is the view of the doomsayers. Out of the remnants of such a dead civilization, another could perhaps arise anew—like a phoenix from the ashes—but this “solution” admits that advanced civilizations don’t survive long after crossing the technological threshold.
Second, our civilization might successfully resolve each of Earth’s global problems as each in turn becomes critical. Resembling a person navigating a minefield, we can take one step at a time, using technology to lighten our burden, to help us progress, and thus survive. This is the view of the technological optimists. This solution seems reasonable at face value, but deeper thought suggests a fundamental dilemma.
To avoid any of our impending worldwide troubles, civilization must be willing to sacrifice. To avert, suppress, or otherwise alleviate any one problem requires our civilization to exercise some restraint. And yet, as we solve them all—and to survive we must solve each and every global problem—the required restraint accumulates. Should our descendants elect to choose this second route into the future, then our species is destined to become less free to do what it wants, more constrained to do exactly whatever is needed to guarantee survival. This second route aims us directly toward a state hallmarked by regimentation—perhaps one that lessens democracy and favors authoritarianism—a state hard to define but one where personal freedom, dignity, curiosity, and many other cherished qualities of human nature are diminished, perhaps even eliminated. Complete stability would seem to imply a stagnated, unprogressive state where human rights are not only absent but perhaps not even understood.
We might then wonder: If curiosity dies, does intelligence die also?
We might also wonder: Do either of these two routes—extinction or stagnation—represent the normal route of cosmic evolution on into the future? Of course, we don’t know.
What we do know is that continued development of our civilization—and thus any further attempt to extend technological longevity—will require a delicate balance between opposing hazards, each of them unacceptable. On the one hand, we face the danger of extinction if even one global problem goes unsolved. On the other hand, we face the temptation of becoming a stagnated society because of the increased stabilization and restraint needed to ensure survival.
After billions of years of evolution, life on Earth has arrived at the greatest possible dilemma for any neophyte technological civilization. Will our generation—humankind at the turning point—make some contribution to the long-term survival of the species? Are we willing to face the issue of survivability of humankind in a world threatened both by physical extermination and by various forms of dehumanization? Is there a narrow path between the danger of extinction and the temptation of stagnation?
A Potential, Lofty Solution Some scientists now suggest that there is a recipe for avoiding stagnation, while still surviving. The vehicle needed to guide us along such an intermediate course may well be a two-fold program of simultaneously colonizing the nearby planets and searching for galactic civilizations. Such a project may sound far out—and literally, it is—but sober reflection suggests that bold, prescient outreach of this sort makes more sense than bland, inward-looking pronouncements offered under the guise of raising social consciousness or reviving religious fervor. Turning inward, while trying to halt change, cannot indefinitely preserve our species on this small planet; looking outward, while accepting change, should now be embraced as the means to our coming of age as an intelligence in the Universe.
Humans can and should begin to terraform and colonize other planets and their moons. This isn’t tantamount to abandoning ship. Nor is this a wild-eyed scheme to look to the stars for solutions to our Earthly problems. (Indeed, our present double-trouble potential for population glut and nuclear war must still be checked by changing the social climate here on Earth, and quickly at that.) Instead, this is a rational program that mostly transcends our present problems, while at the same time identifying a common objective to divert both sides’ military-industrial complexes from misusing vast amounts of human resources. Of greatest importance, a program of partial movement away from our planet would enable us to disperse Earth’s civilization throughout larger pieces of interplanetary real estate—to get “all those eggs out of a single basket,” as noted earlier in this FUTURE EPOCH.
Recall also the criticism of space colonization in this FUTURE EPOCH. Planetary colonization is a demonstrably different proposition. Terraforming, the process of transforming planets or moons into Earth-like objects, may at first sound far-fetched, yet it’s probably cheaper, safer, and more realistic than constructing monstrous interplanetary bottles for people to inhabit the insides of. Planets and their moons provide solid foundations for habitats, and quite naturally so. Some of them, Mars and Venus, for example, have enough mass to retain their own atmospheres, thereby enabling people to reside naturally on the outside. Admittedly, substantial environmental changes would be needed to transform the mostly CO2 atmospheres of those two planets into breathable oxygen. But known natural processes could help, such as the seeding of copious amounts of blue-green algae that could convert their alien atmospheres, via photosynthesis, into oxygen-rich environments.
The prime motive for planetary colonization is the dispersal of the human species. Any of the above-noted global problems is a real danger to societies confined to a single planet. Yet once a society scatters over astronomical distances, it then becomes a good deal less vulnerable to local catastrophe. Invulnerability—that’s the key to the survival of our technological civilization. Individual colonies of dispersed humans might fail to survive, especially if they encounter many of the ailments now or soon to be confronting 21st-century Earthlings. But the chances are lessened that all such colonies would so perish. Even if only one planetary colony were to survive terrestrial and extraterrestrial onslaughts, that would be enough to preserve our civilization, our species. Said another way, when a life form is confined to a single planet, probability theory works against it surviving over the long haul, yet when dispersed across many planets, those same probabilities work in favor of its indefinite survival.
Now is the time to inaugurate a dedicated, preferably international effort to lay the groundwork for planetary colonization. The more quickly we begin to exploit the natural resources of our Solar System, thereby converting some of its matter into biological living space, and especially dispersing our kind throughout a larger volume, the better the chances that Earth’s great experiment—intelligent life—will not end in failure.
The second program that humans should now undertake is a dedicated search for galactic civilizations. Although the chances of success are probably small, do recall that we’ve come to recognize that we inhabit no special place in the Universe. All experimental tests made since Renaissance times embrace the idea that we’re residents of an undistinguished rock, circling an average star, someplace in the suburbs of the Milky Way Galaxy. If we’re examples of anything in the cosmos, it’s probably magnificent mediocrity.
With one exception, there’s nothing unique about planet Earth. The exception is that Earth is the only place in the Universe where we know that life definitely exists. We might prefer to think that cosmic evolution has brought matter to a sufficiently complex state elsewhere in the Universe but, to be truthful, we know of no other location in the entire Universe where life has arisen. To stress a point made at the start of this FUTURE EPOCH, this doesn’t imply that life is necessarily absent beyond our planet. It means that if extraterrestrial life does exist, we haven’t yet become sophisticated enough to know it.
The case favoring the prospects for extraterrestrial life can be summarized by noting what are sometimes called the “assumptions of mediocrity.” Since (1) life on Earth depends on just a few basic molecules and since (2) the atoms composing those molecules are common to all stars, and if (3) the laws of science as we know them apply to every nook and cranny within the Universe, then, given enough time, life may well originate at many places in our Galaxy and galaxies beyond. In other words, given the enormity of space and the vastness of time, cosmic evolution likely drives the emergence of life in many locales throughout the Universe. Even if planets having congenial environments for life are as rare as 1 in a billion star systems, at least several hundred such candidates likely reside in our Galaxy alone.
The opposing view maintains that intelligent life on Earth is the product of extremely fortunate accidents—astronomical, geological, chemical, and biological events that are unlikely to occur anywhere else in the Universe. The grand idea of cosmic evolution is not challenged, in fact it’s also judged correct in this alternative view. Life is still a natural consequence of the evolution of matter; it’s just not inevitable. Simply stated: The steps leading to life—especially intelligent life—are considered so rare as to make it unlikely that any advanced beings reside beyond Earth.
Researchers subscribing to this latter view argue that searches for extraterrestrial beings are unreasonable and unwarranted. They claim that the assumptions underlying the prospects for extraterrestrial intelligence contain too many uncertainties. The search strategies themselves involve additional uncertainties. They conclude that any expenditure of time, effort, and money for a search is unjustified by the meager evidence at hand.
Proponents of a search for extraterrestrials admit there is only a slight chance of making contact in the near future. But they contend that now is the time to test the hypothesis that other technological civilizations inhabit our Galaxy. Failure to do so is tantamount to committing the cardinal sin of pre-Renaissance workers—thinking without experimentally testing.
Earth now stands on the threshold of membership in the community of galactic civilizations—provided we really want to join, and provided such advance aliens really do inhabit the depths of space. With the aid of modern equipment such as radio telescopes, robot space probes, and digital computers, our civilization is now capable of taking what may be the next great evolutionary leap forward—making contact with extraterrestrial intelligent life.
If a galactic empire does exist, we might profit greatly by communicating with its members. We have, after all, only decades ago acquired a technological competence, only recently gained the ability to engage in an interstellar dialogue. Accordingly, we are quite likely to be currently among the dumbest intelligent life forms in the Galaxy.
At the least, discovery of advanced galactic life will assure us that it’s possible for technological civilizations to avoid doomsday—to survive. At the most, by establishing an interstellar dialogue, our civilization may well be able to strive toward a higher level of consciousness heretofore unimagined.
This is not to suggest that contact itself will grant us instantaneously greater intelligence, though it might. Nor will extraterrestrials necessarily provide us with solutions to our global predicaments, though they might. The suggestion now being made by some researchers is that the very program of searching will stretch our imaginations, widen our horizons, and enhance our curiosity. The search itself becomes humankind’s instrument of survival.
Should any of this reasoning be valid, the establishment of a galactic culture might well be the normal route of cosmic evolution—for those who survive by taking it.
I’ve talked about many possible and plausible aspects about how alien life could be, their behaviour and nature and one more thing if they are really existent, where are they? Why haven’t they contacted us? Many idea which I actually imitate are here . Though I tried to consider every scenario but perhaps, I missed one. Contact with aliens also depends upon searching tactics and parameters of aliens along with others. It has already been proposed that aliens may be of different forms with entirely different biochemisty. We know universe is filled with possibility. That’s why we can’t ignore the possibility of aliens being from a flaming environment of acids or freezy atmosphere of saturn like planet. Might they be silicon based or even ammonia or anything completely unknown to us. If they are advanced and have curiousity to know about universe it is expected by nature they would explore planets similar to their own home and they direct their message to planets similar to home planet. If there are really intelligent civilization , possibly we never receive their message cause they are different. Unless we go to saturn or titan or europa and set there a SETI program, then we could have hope. So there are more chances if we get acquainted to alien civilization, it would be more human like but advanced. Really important case scenario! Whatever else we could get in future , who knows?
[Credit: Mark Louis, a regular reader of this blog]
Interstellar Spaceflight How can our civilization search for extraterrestrial life? By what means can we attempt to make this evolutionary leap forward?One obvious way is to develop the capability to travel far outside our Solar System. By involving many nations in the space programs begun by the United States and the Soviet Union, our civilization might be expected eventually to develop the means to travel through interstellar space. However, such technology will not be achieved easily; it may not even be a practical possibility.
A basic problem with interstellar space travel is the quantity of fuel needed for long-duration flights. The damaging effects of galactic radiation is another issue, as are the loneliness and boredom of generations of humans having to spend their entire lives aboard a spacecraft. Consider, for example, a trip to the nearest star system beyond our Solar System, namely Alpha Centauri ~4.3 light-years away. With a constant flight velocity of 50 km/s, which approximates the speed of our fastest robotic space probes, this trip would take ~25,000 years. That’s a fast enough velocity to escape the Solar System, yet 250 centuries would still be needed to reach the closest star system. Contrast this duration with, for instance, the 15 centuries since the fall of the Roman Empire or the 50 centuries since the construction of the Pyramids. Even if fuel for the spacecraft and food for the inhabitants were available, such a flight would take an incredibly long time by human standards.
This example assumes a spacecraft traveling at a velocity much less than the velocity of light. In fact, 50 km/s equals less than 0.02% of light velocity. We might imagine that our civilization could someday become smart enough to achieve flight velocities close to 100% of light velocity, which might dramatically reduce travel times by means of special relativistic effects—but we would probably be fooling ourselves.
Relativistic space flight seems nice in theory, for flight durations could seemingly be diminished, as has been suggested by legions of science-fiction writers. But in practice, there’s a problem. Spacecraft traveling at speeds close to light velocity cannot be easily refueled. A reasonably sized craft of, for example, 104 kg (10 tons) would need more than a billion kilograms (a million tons) of hydrogen fuel just to accelerate it to 10% of light velocity. These numbers assume that such a spacecraft derives its energy from a hydrogen-helium fusion reaction; the helium squirts out the rear and the spacecraft lurches forward via Newton’s third law. However, to reach relativistic speeds, namely >90% of light velocity, would require so much on-board fuel as to make this proposition ridiculous.
The idea of using interstellar hydrogen gas as a spacecraft moves through space seems equally futile. To accelerate to 10% of light velocity would require a gigantic scoop kilometers across. Such a scoop need not be made of physical material; rather, it could be a huge electromagnetic field, capable of harvesting charged protons needed for fuel. Yet to reach relativistic speeds would require such a scoop to be of light-year dimensions. And furthermore, according to the proven rules of relativity, the spacecraft’s mass would increase relative to the interstellar medium from which it captured its fuel, which would require even more fuel and so on, making this a self-defeating proposition. Given the laws of physics as we currently know them, relativistic space flight seems destined to remain science fiction. Probably no intelligent civilization would or could do it.
These arguments don’t necessarily prohibit traveling through interstellar space at much slower speeds. If our descendants can overcome harmful radiation and severe boredom during long, long journeys, interstellar travel might someday become feasible with modest fuel supplies and speeds of a few percent of light velocity. To do so, however, would mean not just generations of space travel, but flights lasting thousands and perhaps even millions of years.
Equally possible, these practical problems might never be solved, or perhaps our civilization will not survive long enough even to attempt interstellar space flight. Future generations of Earthlings might well conclude that it’s simply impractical to travel over large galactic distances. If so, we will be forever confined to our Solar System and at best a handful of nearby stars.
Accordingly, it seems unlikely that human space flight is a useful means to seek contact with extraterrestrials. Even with the most optimistic estimates of the many factors in the Drake equation, galactic civilizations (if they exist at all) are probably spread out like small islands within the vast sea of galactic space. For example, with all the interior factors of our equation maximized and the average technological lifetime equal to 1000 years, we might conclude that 1000 advanced civilizations currently reside in our Galaxy. Given the size and shape of the Milky Way, ~3000 light-years would then separate any two adjacent civilizations. Such large distances force the word “neighboring” to take on new meaning.
Even if the average lifetime of galactic civilizations is 1 million years, our most optimistic estimates suggest that each is separated by ~300 light-years. To have a reasonable hope of successful contact, hundreds, perhaps thousands, of sorties would need to be launched toward candidate star systems. All in all, interstellar space flight is both impractical and uneconomical either at the present time or in the foreseeable future. It may never become feasible.
Interstellar Probes Other methods might be used to search for extraterrestrial intelligence in the Galaxy. Imagine, for example, launching many robot space probes, each with a velocity sufficient to escape our Solar System. Each probe would eventually reach a star system judged a good candidate for intelligent life, where it would orbit the star, looking and listening for evidence of life on one of the planets. Such a probe could be programmed to detect the leakage of electromagnetic radiation arising from the daily activities of a technological civilization. It might succeed immediately upon arriving, should an advanced civilization already be thriving. Or a probe might need to bug an alien star system for thousands of years before seeing or hearing any type of planetary activity resembling our radio, television, military radar, or whatever. Once the robots did detect any sign of intelligence, they would send a radio signal back to Earth, letting us know that a technological civilization has emerged.
Robot probes offer a couple of advantages in the search for extraterrestrials: They would be neither bored by the long duration of the flight, nor harmed by the harsh radiation of interstellar space. But a disadvantage with this method of contact is that, once again, it would seem uneconomical for the foreseeable future. To bug all single F-, G-, and K-type stars within 1000 light-years of Earth would require about a million probes. Given the number of days in a year, one probe would need to be launched every day for nearly 3000 years. Aside from these formidable logistics problems, the cost of such a program would be staggering.
In a sense, our civilization has already launched several such probes, although they lack the sophistication of the robots just noted. Figure is a reproduction of a plaque mounted aboard the American Pioneer 10 spacecraft launched in the mid-1970s. Similar information was also included aboard the American Voyager spacecraft launched a few years later. After visiting the outer planets, these probes are now on their way out of the Solar System, but they have no specific destination thereafter.
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— This is a replica of a plaque mounted onboard the Pioneer 10 spacecraft. Key features of the plaque include: a scale drawing of the spacecraft itself, as well as a man and a woman (right center); a schematic diagram of a hydrogen atom undergoing a change in energy (top left); a starburst pattern representing various pulsars and the frequencies of their radio waves usable to estimate when the craft was launched (middle left); and a depiction of the Solar System, showing that the spacecraft left the third planet from the Sun and passed the fifth planet on its way into outer space (bottom). All the drawings have computer (binary) coded markings from which actual sizes, distances, and times can be derived. (Carl Sagan)
Even if these American spacecraft do accidentally encounter an alien star system housing an advanced civilization, these machines are incapable of reporting that news back to Earth. Should a civilization on the other end intercept the probe, they should be able to unravel most of its contents using the universal language of “mathematiceese.” The caption to Figure notes how aliens might interpret from where and when the Pioneer and Voyager probes were originally launched. They would then know that we are here (or were when the probes were sent), although we would remain unaware of their existence. Perhaps not such a good thing.
So methods that rely on space travel, either crewed or uncrewed, don’t seem to hold much promise in contacting extraterrestrial intelligent life. One can always argue that future technological breakthroughs may someday make such projects more favorable. Indeed, the microelectronic revolution now under way might eventually make unmanned probes more feasible. But given what we know now, long-distance space travel seems logistically and economically unlikely.
Aside from these practical problems, some scientists argue that it’s not a smart idea to signal extraterrestrials actively. As noted earlier in this FUTURE EPOCH, our recent emergence as a technologically competent civilization implies that we’re now among the dumbest technological intelligences in the Galaxy. Any other civilization either that we discover, or that discovers us, will almost surely be more advanced than us. Consequently, a healthy degree of skepticism is warranted. After all, if you were lost in a jungle populated by unknown natives, you would be wise not to yell, scream, or send up smoke signals to let them know of your presence. It’s a lot safer to explore your environment quietly for a while, to listen to the sound of the drums, and to get a feeling for their intentions.
Some anthropologists have even speculated about the behavior of advanced galactic civilizations. If extraterrestrials behave even remotely like human civilizations on Earth, then the most advanced aliens might naturally try to dominate all others. Indeed, the “smarter” species have often taken advantage of others throughout the history of life on Earth. Even so, the aggressiveness of Earthlings may not in any way apply to extraterrestrials. And in any case, the vast distances separating galactic civilizations would probably prohibit a civilization on one planet from physically dominating or enslaving a less advanced civilization on some other planet. In fact, physical contact among different cosmic civilizations may not be biologically desirable; what is healthy for one life form might be a disease to another.
Radio CommunicationA third technique is much cheaper than either of the two methods noted above and has many advantages. This method is designed to make contact with extraterrestrials using only electromagnetic radiation, in particular it doesn’t utilize any kind of hardware traveling through space. The technique is economically feasible, can be undertaken with existing equipment, and doesn’t reveal our presence should some extraterrestrials be hostile.
This third method uses radiation as the fastest known means of transferring information from one place to another. Since light and other types of high-frequency radiation are heavily scattered while moving through dusty interstellar space, long-wavelength radio radiation seems the best way to transfer information in the plane of the Galaxy where civilizations are likely to be located. Accordingly, radio telescopes on Earth would be used to listen passively for radio signals emitted by someone else. No radiation would be transmitted by our civilization toward distant star systems. Best of all, we have already invented the equipment needed to detect such alien radio signals. Some preliminary searches are now underway, thus far without success.
Radio searches of this type are not without problems, however. The foremost problem is that this method assumes that extraterrestrials are in fact broadcasting radio signals for one reason or another. If they aren’t, this search technique will fail. Another problem concerns the need to distinguish radio signals artificially generated by advanced civilizations from signals naturally emitted by interstellar gas clouds; interference of all kinds could be a major impediment. Other problems include the direction in which to aim our radio telescopes, the frequency at which to tune our receivers, and time of day when to listen.
Such a search could be undertaken by following either of two strategies. One strategy attempts to eavesdrop on the radio radiation normally leaking from some planet while its civilization goes about its daily business. A sample of what might be expected can be gained by reversing the problem and examining the appearance of Earth from afar. Figure shows the pattern of radio signals unintentionally leaked into space by our civilization. From the viewpoint of some distant observer, the spinning Earth emits a bright flash of radio radiation every few hours. The flashes result from the periodic rising and setting of hundreds of radio stations and television transmitters. Because the great majority of these transmitters are clustered in eastern United States and western Europe, and because they emit their radiation parallel to the ground where people live, a distant observer would detect blasts of radiation leaking from Earth as our planet rotates each day. This radiation races out into space as a growing sphere of radio, television, and other electromagnetic signals (such as radar). It’s been doing so since the invention of these technologies several decades ago. In fact, Earth is now a more intense radio source than the Sun—thanks to our technological civilization.
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FIGURE — Radio radiation now leaks from Earth into space because of the daily activities of our technological civilization. (a) FM radio and non-cable television transmitters broadcast their energy parallel to Earth’s surface, so they send a great “sheet” of electromagnetic radiation into interstellar space, producing the strongest signal in any given direction when they happen to lie on Earth’s horizon. (b) Because the great majority of transmitters are clustered in the eastern United States and western Europe, a distant observer would detect blasts of radiation from Earth as our planet rotates each day. (Prentice Hall)
If any advanced civilizations reside within ~50 light-years of Earth, we have already broadcast our presence to them. Whether or not the extraterrestrials have received the message, we don’t yet know. But if they have, they might well have concluded that we aren’t so intelligent, given the content of our radio and television programs.
This eavesdropping strategy resembles the space probe technique discussed earlier, although here the “bugging” of other planetary systems can be accomplished from Earth using large radio telescopes. However, such telescopes now in operation are likely sensitive enough to eavesdrop on only a few of the nearest star systems. Remember, the strength of radiation decreases with the square of the distance.
We do currently have the engineering ability to build a huge detector that could intercept the hodgepodge of radio, radar, and television signals wastefully leaked into space by other, distant civilizations—namely, ones like our own. Figure 8.30 shows the major features of a gigantic array of radio telescopes capable of eavesdropping on Earth-like civilizations within ~1000 light-years of us. Called Project Cyclops, this vast machine hasn’t yet been built—and it may never be since the price tag for such a device is ~$20 billion (1995 dollars). Its construction is currently improbable, given all the social, bureaucratic, and militaristic demands for taxpayers’ money. Keep in mind, though, that this cost is roughly equivalent to the price tag of one American aircraft carrier or a fleet of Russian warheads. It’s simply a matter of where our society wants to place its priorities.
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FIGURE — This is a design sketch of a gigantic array of 1000 interconnected radio telescopes, called Project Cyclops. Such a device could be used to eavesdrop on civilizations much like our own, provided they are within ~1000 light-years of Earth. (NASA)
Another radio-based strategy might be used to search effectively for extraterrestrial intelligent life. However, this one relies on a single, key assumption, the validity of which is totally unknown. The assumption is that at least one advanced civilization is beaming strong radio signals toward many star systems in the Galaxy—our Sun among them—actively hoping to contact us. Such a radio beacon, set up by an alien broadcaster specifically to attract our attention, might be detectable with radio telescopes already built on Earth. But there’s a catch here too, as other concerns hinder this passive, optimistic search strategy. To give but one example, in what direction should we listen? Even if we limit our targets to Sun-like stars, ~500 of them exist within only ~300 light-years of Earth. Any one of them could have a planetary civilization that is transmitting toward us. To be thorough, we would need to sample every such star system.
The basic issue in estimating the number of extraterrestrial civilizations we could contact isn’t the extent to which a society develops technology. Rather, the real issue is the degree to which a society generates curiosity and maintains it for long periods of time. A two-way interstellar dialogue requires, not only technological competence, but also sufficient motivation on both ends—ours and theirs. How motivated is a society to communicate with other societies beyond its own home planet? How universal is curiosity? How persistent is it? Would the residents of every inhabited planet have a deep desire to know if others exist in the Universe.
Humans on Earth do seem to have a genuine curiosity about the Universe. Since consciousness dawned, many humans have wondered about who they are and where they came from. Many have also thought about extraterrestrial life beyond Earth. But how long does this curiosity last? Does technologically competent intelligent life remain curious indefinitely?
Curiosity may wax and wane over the ages, as it has on our planet. The Greeks and Romans were curious, the barbarians of the Middle Ages apparently less so; now in post-Renaissance times, we are again highly curious people. Perhaps other advanced civilizations reside in the depths of space, but their societies have reached the stage of mental and physical stagnation broached earlier in this FUTURE EPOCH. Maybe their curiosity is gone forever. Again, we repeat our earlier query: If curiosity dies, does intelligence die also?
Distressingly, if the average technological lifetime is only 1000 years, then, as noted above, the average distance separating galactic civilizations would be ~3000 light-years. Hence, among our local realm of several thousand Sun-like stars, we would expect only one technological civilization. Since we are such a civilization, we would then be that one—the only one within this part of the Galaxy. To have any real hope of success, then, the search strategy must be directed toward many additional candidate stars far beyond 1000 light-years. Over such vast distances, a two-way dialogue will not exactly be a snappy conversation. A reply to an initial “Hello” may take thousands of years.
As if the problem of where to search weren’t enough, there’s another dilemma. At what frequency should we listen for their beacon? The electromagnetic spectrum is enormous; the radio domain alone covers many orders of magnitude in wavelength. To hope to detect a signal at some unknown radio frequency is like searching for a needle in a haystack. The technique would seem doomed to failure, unless we have some prior information concerning the likely frequencies on which aliens might transmit.
Fortunately, some basic arguments suggest that civilizations will probably communicate at wavelengths around 20 cm. The basic building blocks of the Universe, namely hydrogen (H) atoms, naturally radiate near 21-cm wavelength. And, one of the simplest molecules, hydroxyl (OH), radiates near 18-cm wavelength. Given that these two substances form water (H2O) and that water is likely to be the interaction medium for life anywhere, some researchers have proposed that the interval 18 – 21 cm is the best part of the spectrum for civilizations to transmit or listen. Called the “water hole,” this radio interval might serve as an oasis where all advanced galactic civilizations conduct their electromagnetic business.
The water-hole frequencies comprise only a guess, but they’re supported by other arguments as well. In particular, the wavelength domain from 18 to 21 cm is precisely that part of the entire electromagnetic spectrum—from radio waves all the way across to gamma rays—for which the galactic static from stars and interstellar clouds is minimized. Furthermore, the atmospheres of typical planets, such as our own, are also expected to interfere least at these wavelengths.
Figure shows the water hole’s position in the radio spectrum. This figure also plots the amount of natural emission from our Galaxy and from Earth’s atmosphere, showing how the water hole is positioned within the quietest part of the spectrum. Thus this water hole seems like a good choice for the frequency of an interstellar beacon, although we can’t be sure of this reasoning until contact is actually achieved. Perhaps some other transmitting frequency is better for reasons unknown to us at this time.
FIGURE — The “water hole” is bounded by the natural emission frequencies of the hydrogen (H) atom at 21-cm wavelength and the hydroxyl (OH) molecule at 18-cm wavelength. The dashed curve sums the natural emissions of our Galaxy and of a planet’s atmosphere (in this case Earth’s). This sum is minimized near the water hole frequencies. Perhaps all smart civilizations conduct their interstellar communications within this quiet “electromagnetic oasis”.
A few passive radio searches are now in progress at frequencies in and around the water hole, yet so far nothing resembling alien signals has been detected. But that’s not surprising, given the small efforts made to date. Attempts to detect extraterrestrials have been so brief in relation to the task at hand that they resemble a “Columbus” who, upon searching for a new route to the Indies, ventured about a kilometer off the coast of Spain. To maximize the chance for success, a dedicated effort is needed—one perhaps requiring hundreds of years of searching on a continuous basis. To have much hope of making contact, we will probably need to monitor millions of stars.
Many uncertainties plague this sort of search strategy, the foremost being the desire of any civilization to transmit. From what we know, transmitting is boring, expensive, and potentially dangerous. Accordingly, perhaps everyone is just listening. If so, then the prospects for contact are dim; to create a dialogue, somebody’s got to start talking.
Other uncertainties concern “language.” Will galactic civilizations be able to find a common language? This puzzle includes not only the difficulty of matching the frequencies of transmission and reception, but also the potential problem of ever being able to understand or appreciate the content of the message. This may be especially troublesome if the transmitting civilization is much more advanced than ourselves. Even a few centuries more progress would likely give them technological prowess hardly imagined here on Earth; just think of the advances we’ve made in the 20th century alone. Extraterrestrials may use means of contact entirely foreign to us. We may be unable to detect their signals or decipher their code. They may be as uncommunicative with us as we are with, for example, dolphins or even ants. All such civilizations may be doomed to loneliness for as long as each survives.
On the other hand, if aliens are eager to contact emerging civilizations in our Galaxy, they will realize that less sophisticated means must be used. They would want to make the task as easy as possible for us, thereby transmitting signals that inexperienced civilizations like ourselves could detect and decipher. Their language would probably be built around mathematics, since counting should be universal: 2 + 2 ought to equal 4 everywhere.
Figure exemplifies how mathematics can be used to send messages through space. In this case, no words are needed, just a picture.
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FIGURE — In this hypothetical transmission (a), a message is buried within a long series of digital information (dots and dashes, or ones and zeroes). The total number of digits is 725, which is a product of two whole integers 25 and 29. When arranged in a geometrical pattern having 25 rows and 29 columns (b), the message is unrecognizable. But, when arranged in 29 rows and 25 columns (c), the message is clear.
All the many combined uncertainties cause some researchers to be pessimistic. They argue that a search for extraterrestrials is unreasonable and unwarranted. They claim that the assumptions needed to estimate the prospects for extraterrestrial intelligence contain too many unknowns. The search strategy itself contains additional unknowns. They conclude that any expenditure of time, effort, or money for a search is unsupported by the meager evidence at hand.
Proponents argue that we have good reason to suspect that extraterrestrials exist somewhere, given the relative ease of our development on Earth. They admit that we have only a minute chance of making contact in the near future. But they argue that now is the time to test the theory that advanced civilizations inhabit the Galaxy. To fail to try, is to commit the cardinal sin of pre-Renaissance workers—thinking without experimentally testing. Failure to try might also cut prematurely short humankind’s natural exploratory drive. Our longevity as a civilization may be shortened for the very reason that we didn’t undertake the search.
One thing is worth remembering: The space surrounding all of us could be, right now, inundated with radio signals from alien civilizations. If we only knew the proper direction and frequency, we might be able to make one of the most startling discoveries of all time. The result would not only likely provide whole new opportunities to know and understand the cosmic evolution of energy, matter, and life in the Universe, but it might also be the key to our civilization’s long-term survival along the arrow of time.
Wargames like GDW’s STAR CRUISER describe interplanetary combat as being like hide and go seek with bazookas. Stealthy ships are tiny needles hidden in the huge haystack of deep space. The first ship that detects its opponent wins by vaporizing said opponent with a nuclear warhead. Turning on active sensors is tantamount to suicide. It is like one of the bazooka-packing seekers clicking on a flashlight: all your enemies instantly see and shoot you before you get a good look. You’d best have all your sensors and weapons far from your ship on expendable remote drones.
Well, that turns out not to be the case.
The “bazooka” part is accurate, but not the “hiding” part. If the spacecraft are torchships, their thrust power is several terawatts. This means the exhaust is so intense that it could be detected from Alpha Centauri. By a passive sensor.
The Space Shuttle’s much weaker main engines could be detected past the orbit of Pluto. The Space Shuttle’s manoeuvering thrusters could be seen as far as the asteroid belt. And even a puny ship using ion drive to thrust at a measly 1/1000 of a g could be spotted at one astronomical unit.
This is with current off-the-shelf technology. Presumably future technology would be better.
Now I know you do not want to accept the fact that stealth in space is all but impossible. This I know from experience (Every day I have new email from somebody who thinks they’ve figured out a way to do it. So far all of them have had fatal flaws.). The only thing that upsets budding SF writers more is Albert Einstein denying them their faster than light starships. But don’t shoot me, I’m just the messenger. The good folk on the usenet newsgroup rec.arts.sf.science went through all the arguments but it all came to naught.
Not that that’s gonna stop you from trying.
It is a truth universally acknowledged that any thread that begins by pointing out why stealth in space is impossible will rapidly turn into a thread focusing on schemes whereby stealth in space might be achieved.
If you want to really argue on this topic, I’d advise you to cut out the middle man and go directly to rec.arts.sf.science and lay your case out before the experts. You might also want to review the section on Respecting Science.
Most of the arguments on thermo and space detection run through a predictable course of responses:
1) “Space is dark. You’re nuts!”
2) “OK, there’s no horizon, but the signatures can’t be that bright?”
3) “OK, the drive is that bright, but what if it’s off?”
4) “But it’s not possible to scan the entire sky quickly!”
5) “OK, so the reactors are that bright, what if you direct them somewhere else…”
6) “What if I build a sunshade?”
7) “OK, so if I can’t avoid being detected by thermal output, I’ll make decoys…” “Arrgh. You guys suck all the fun out of life! It’s a GAME, dammit!”
“Well FINE!!”, you say, “I’ll turn off the engines and run silent like a submarine in a World War II movie. I’ll be invisible.” Unfortunately that won’t work either. The life support for your crew emits enough heat to be detected at an exceedingly long range. The 285 Kelvin habitat module will stand out like a search-light against the three Kelvin background of outer space.
And if you are hoping to lose your tiny heat signature in the vastness of the sky, I’ve got some bad news for you. Current astronomical instruments can do a complete sky survey in about four hours, or less.
Now after six million years of evolution, where do we go next? How will evolution, our newly arrived intellect, our primal drives and the powerful technologies we continually create, change us?
Our current situation is unlike anything nature has seen before because we are not simply a by-product of evolution, we are ourselves now an agent of evolution. We are this animal, filled with ancient emotions and needs, amplified by our intellects and a conscious mind, embarking on a new century where we are creating fresh tools and technologies so rapidly that we are struggling to keep pace with the very changes we are bringing to the table.
Where will this lead?
Will we develop new brain modules, new appendages, revamped capabilities just as we have over the past six million years? Absolutely, but probably not in the way we suspect. It appears, if we look closely, that the DNA that has been such a perfect ally in the evolution of life, may itself be in for a revamping. Evolution may be prowling for a new partner. And the partner may be us, or at least the technologies we make possible.
The irony is that it takes a being like us, a human being, to bring about change this fundamental.
The job requires an amalgamation of high intelligence and emotion, conscious intent, primal drives and great quantities of knowledge made possible by minds that can communicate in highly complex ways. If you pulled any one of these out, the future, at least one involving intelligent, conscious creatures like us, would fall apart. It takes not just cleverness, but passion, sometimes fear, fired by focused intention, to create and invent.
Without this combination there would be no technologies, no wheels or steam engines or nuclear bombs or computers. And there would be nothing like the world we live in today. At best we would still be huddled in the black African night, eking out whatever existence the predators waiting in the darkness around us would allow. Not even fire would be our friend.
But the traits that have shaped us into the human beings we are have endowed us with strange abilities, and they are hurtling us into a future radically unlike the past out of which we have emerged. And that future will be profoundly different from anything most of us can imagine.
We would manage this by boosting robots up the evolutionary ladder, roughly in decade-long increments, making them smarter, more mobile, more like us. First they would be as intelligent as insects or a simple guppy (we are about there right now), then lab rats, then monkeys and chimps until, finally one day, the machines would become more adept and adaptive than their makers.
That, of course, would quickly raise the question:
“Now who is in charge?”
Would Homo sapiens, after some 200,000 years living on top of the planet’s food chain, no longer rule the roost?
Would we, in the cramped space of this evolutionary ellipsis, find ourselves playing Neanderthal to technologies that had become, like us, self-aware – the first conscious tools built by a conscious tool-making creature?
The unavoidable answer would be, yes.
Evolution will have found through us a new way to make a new creature; one that could forsake its ladders of DNA and the fragile, carbon-based biology that nature had been using for nearly four million millennia to manage the job.
The “end” would not come in the form of a Terminator style invasion, it would simply unfold in the natural course of evolutionary events where one species, better adapted to its environment replaces another that is no longer very fit to continue. Except the new species wouldn’t be cobbled out of DNA, it would be fashioned from silicon, alloy, and who knows what else, invented by us. But once successfully invented, we wouldn’t be necessary any more.
Whether events will play out like this or not remains to be seen.
But Moravec’s scenario makes a point – the world and the life upon it changes, and simply because we are the agents of change, doesn’t mean we won’t be affected by it.
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It is strange to think of the invention of machines, even robotic ones, as having anything to do with Darwin’s natural selection.
We usually regard evolution as biological – a world of cells, DNA and “living” creatures. And we think of our machines as unalive, unintelligent and shifted by economic forces more than natural ones. But it isn’t written anywhere that evolution has to be constrained by what we traditionally think of as biology. In fact each day the lines between biology and technology, humans and the machines we create are blurring.
We are already part and parcel of our technology.
Since the day Homo habilis whacked his first flint knife out of flakes of flint, it has been difficult to know whether we invented our tools or our tools invented us. The world economy would crash if its computer systems failed. We can’t live without laptops, palmtops, cell phones or iPods, which grow continually smaller and more powerful.
We regularly engineer genes, despite the raging debates over stem cell therapy. A human being will very likely be cloned within the next five years. We now have computer processors working at the nano (molecular) level and microelectromechanical machines (MEMS) that operate at cellular dimensions. Already electronic prosthetics make direct connections with human nerves, and electronic brain implants for Parkinson’s disease and weak hearts are common place. Scientists are even experimenting with electronic, implantable eyes.
New clothing weaves digital technologies into their fiber and brings them a step closer to being a part of us. The military are working on “battle-suits” that will fit like gloves, a kind of second skin and amplify a soldier’s senses, strength and ability to communicate, even triangulate the direction of a bullet headed his or her way.
What next? Speech, writing and art enabled us to share inner feelings in new and powerful ways.
But it takes months or years to learn a new language or how to play the piano or master the art of engineering bridges and buildings.
Will new technologies that accelerate communication (virtual reality, telepresence, digital implants, nanotechnology) create new ways to communicate that can by-pass speech?
Will we someday communicate by a kind of digital telepathy, downloading information, experiences, skills, even emotions the way we download a file from the Internet to our laptop?
Will we become machines, or will machines become more powerful versions of us?
And if any of this comes to pass, what ethical issues do we face?
At what point to do we stop being human?
Lynn Margulis, probably the world’s leading microbiologist, has argued that this blurring of technology and biology isn’t really all that new.
She has observed 1 that the shells of clams and snails are a kind of technology dressed in biological clothing. Is there really that much difference between the vast skyscrapers we build or the malls in which we shop, even the cars we drive around, and the hull of a seed?
Seeds and clam shells, which are not alive, hold in them a little bit of water and carbon and DNA, ready to replicate when the time is right, yet we don’t distinguish them from the life they hold. Why should it be any different with office buildings, hospitals and space shuttles?
Put another way, we may make a distinction between living things and the tools those things happen to create, but nature does not.
The processes of evolution simply witness new adaptations and preserve those that perform better than others. That would make Homo habilis’s first flint knife a form of biology as sure as a clamshell, one that set our ancestors on a fresh evolutionary path just as if their DNA had been tweaked to create a new, physical mutation, say an opposable thumb or a big toe.
Even if these technological adaptations were outside what we might consider normal biological bounds, the effect was just as profound, and far more rapid. In an evolutionary snap, that first flint knife changed what we ate and how we interacted with the world and one another. It enhanced our chances of survival. It accelerated our brain growth which in turn allowed us to create still more tools which led to yet bigger brains.
And on we went, continually and with increasing speed and sophistication, fashioning progressively more complex technologies right up to the genetic techniques that enable us to fiddle with the self-same ribbons of our chromosomes that made the brains that conceived tools in the first place. If this is true, all of our technologies are an extension of us, and each human invention is really another expression of biological evolution.
Moravec and Margulis aren’t alone in asking questions that force us to bend our traditional thinking about evolution.
Scientist and inventor Ray Kurzweil has, like Moravec, pointed out that the rate of technological change is increasing at an exponential rate. Also like Moravec, he foresees machines as intelligent as we are evolving by mid century. Unlike Moravec he doesn’t necessarily believe they will arrive in the form of robots.
Initially Kurzweil sees us reengineering ourselves genetically so that we will live longer and healthier lives than the DNA we were born with might normally allow. We will first rejigger genes to reduce disease, grow replacement organs, and generally postpone many of the ravages of old age. This, he says, will get us to a time late in the 2020s when we can create molecule-sized nanomachines that we will program to tackle jobs our DNA never evolved naturally to undertake.
Once these advances are in place we will not simply slow aging, but reverse it, cleaning up and rebuilding our bodies molecule by molecule. We will also use them to amplify our intelligence; nestling them among the billions of neurons that already exist inside our brains. Our memories will improve; we will create entirely new, virtual experiences, on command, and take human imagination to levels our currently unenhanced brains can’t begin to conceive.2
In time (but pretty quickly) we will reverse engineer the human brain into a vastly more powerful, digital version.
This view of the futures isn’t fundamentally different from Moravec’s brain-to-robot download, except it is more gradual. Either way we will have melded with our technology if, in fact, those barriers ever really existed in the first place, and in the end, erase the lines between bits, bytes, neurons and atoms.
Or looked at another way, we will have evolved into another species.
We will no longer be Homo sapiens, but Cyber sapiens – a creature part digital and part biological that will have placed more distance between its DNA and the destinies they force upon us than any other animal. And we will have become a creature capable of steering its own evolution (“cyber” derives from the Greek word for a ship’s steersman or navigator – kybernetes). The world will face an entirely new state of affairs.
Why would we allow ourselves to be displaced? Because in the end, we won’t really have a choice. Our own inventiveness has already unhinged our environment so thoroughly that we are struggling to keep up. In a supreme irony we have created a world fundamentally different from the one into which we originally emerged.
A planet with six and a half billion creatures on it, traveling in flying machines every day by the millions, their minds roped together by satellites and fiber optic cable, rearranging molecules on the one hand and leveling continents of rain forest on the other, growing food and shipping it overnight by the trillions of tons – all of this is a far cry from the hunter-gatherer, nomadic life for which evolution had fashioned us 200,000 years ago.
So it seems the long habit of our inventiveness has placed us in a pickle. In the one-upmanship of evolution, our tools have rendered the world more complex and that complexity requires the invention of still more complex tools to help us keep it all under control. Our new tools enable us to adapt more rapidly, but one advance begs the creation of another, and each increasingly powerful suite of inventions shifts the world around us so powerfully that still more adaptation is required.
The only way to survive is to move faster, get smarter, change with the changes, and the best way to do that is to amplify ourselves eventually right out of our own DNA so we can survive the new environments – physical, emotional and mental – that we keep recreating.
Is all of this too implausible to consider? Will Homo sapiens really give way to Cyber sapiens that seamlessly integrate the molecular and digital worlds just as our ancestors merged the technological and biological worlds two million years ago?
Evolution has presided over stranger things. It took billions of years before the switching and swapping of genes brought us into existence. Our particular brain then took 200,000 years to get us from running around in skins with stone weapons to the world we live in today. Evolution is all about the implausible. And the drive to survive is a relentless shaper of the seemingly impossible. We ourselves are the best proof.
If all of this should happen; if DNA itself goes the way of the dinosaur, what sort of creature will Cyber sapiens be?
In some ways we can’t know the answer anymore than Homo erectus could imagine how his successors would someday create movies, invent computers and write symphonies.
Our progeny, our “mind children,” will certainly be more intelligent with brains that are both massively parallel, like the current version we have, and unimaginably fast.
But what of those primal drives that we carry inside our skulls, and those non-verbal, unconscious ways of communicating?
What of laughter and crying and kissing?
Will Cyber sapiens know a good joke when he hears one, or smile appreciatively at a fine line of poetry?
Will he tousle the machine made hair of his offspring, hold the hand of the one he loves, kiss soulfully, wantonly and uncontrollably?
Will there be a difference between the “brains” and behaviors of he and she?
Will there even be a he and a she?
And what of pheromones and body language and nervous giggles?
Maybe they will have served their purpose and gone away…
Will Cyber sapiens sleep, and if they do, will they dream?
Will they connive and gossip, grow mad with jealousy, plot and murder?
Will they carry with them a deep, if machine made, unconscious that is the dark matter of the human mind, or will all of those primeval secrets be revealed in the bright light cast by their newly minted brains?
We may face these questions sooner than we imagine. The future gathers speed every day.
I’d like to think the evolutionary innovations and legacies that have combined to make us so remarkable, and so human, won’t be left entirely behind as we march ahead. Perhaps they can’t be. After all, evolution does have a way of working with what is already there, and even after six million years of wrenching change, we still carry with us the echoes of our animal ancestors.
Maybe the best of those echoes will remain.
After all, as heavy as some baggage can be, preserving a few select pieces might be a good thing, even if we are freaks of nature.
Any time you allege a conspiracy is afoot, especially in the field of science, you are treading on thin ice. We tend to be very skeptical about conspiracies–unless the Mafia or some Muslim radicals are behind the alleged plot. But the evidence is overwhelming and the irony is that much of it is in plain view.
The good news is that the players are obvious. Their game plan and even their play-by-play tactics are transparent, once you learn to spot them. However, it is not so easy to penetrate through the smokescreen of propaganda and disinformation to get to their underlying motives and goals. It would be convenient if we could point to a plumber’s unit and a boldface liar like Richard Nixon, but this is a more subtle operation.
The bad news: the conspiracy is global and there are many vested interest groups. A cursory investigation yields the usual suspects: scientists with a theoretical axe to grind, careers to further and the status quo to maintain. Their modus operandi is “The Big Lie” — and the bigger and more widely publicized, the better.
They rely on invoking their academic credentials to support their arguments, and the presumption is that no one has the right to question their authoritarian pronouncements that:
there is no mystery about who built the Great Pyramid or what the methods of construction were, and the Sphinx shows no signs of water damage
there were no humans in the Americas before 20,000 BC
the first civilization dates back no further than 6000 BC
there are no documented anomalous, unexplained or enigmatic data to take into account
there are no lost or unaccounted-for civilizations.
Let the evidence to the contrary be damned!
Personal Attacks: Dispute over Age of the Sphinx and Great Pyramid
In 1993, NBC in the USA aired The Mysteries of the Sphinx, which presented geological evidence showing that the Sphinxwas at least twice as old (9,000 years) as Egyptologists claimed. It has become well known as the “water erosion controversy”. An examination of the politicking that Egyptologists deployed to combat this undermining of their turf is instructive.Giza pyramids and how.
Self-taught Egyptologist John Anthony West brought the water erosion issue to the attention of geologist Dr Robert Schoch. They went to Egypt and launched an intensive on-site investigation. After thoroughly studying the Sphinx first hand, the geologist came to share West’s preliminary conclusion and they announced their findings.
Dr Zahi Hawass, the Giza Monuments chief, wasted no time in firing a barrage of public criticism at the pair. Renowned Egyptologist Dr Mark Lehner, who is regarded as the world’s foremost expert on the Sphinx, joined his attack. He charged West and Schoch with being “ignorant and insensitive”. That was a curious accusation which took the matter off the professional level and put the whole affair on a personal plane. It did not address the facts or issues at all and it was highly unscientific.
But we must note the standard tactic of discrediting anyone who dares to call the accepted theories into question. Shifting the focus away from the issues and “personalizing” the debate is a highly effective strategy–one which is often used by politicians who feel insecure about their positions. Hawass and Lehner invoked their untouchable status and presumed authority. (One would think that a geologist’s assessment would hold more weight on this particular point.)
A short time later, Schoch, Hawass and Lehner were invited to debate the issue at the American Association for the Advancement of Science. West was not allowed to participate because he lacked the required credentials.
This points to a questionable assumption that is part of the establishment’s arsenal: only degreed scientists can practice science. Two filters keep the uncredentialled, independent researcher out of the loop: (1) credentials, and (2) peer review. You do not get to number two unless you have number one.
Science is a method that anyone can learn and apply. It does not require a degree to observe and record facts and think critically about them, especially in the non-technical social sciences. In a free and open society, science has to be a democratic process.
Be that as it may, West was barred. The elements of the debate have been batted back and forth since then without resolution. It is similar to the controversy over who built the
This brings up the issue of The Big Lie and how it has been promoted for generations in front of God and everyone. The controversy over how the Great Pyramid was constructed is one example. It could be easily settled if Egyptologists wanted to resolve the dispute. A simple test could be designed and arranged by impartial engineers that would either prove or disprove their longstanding disputed theory–that it was built using the primitive tools and methods of the day, circa 2500 BC.
Why hasn’t this been done?
The answer is so obvious, it seems impossible: they know that the theory is bogus. Could a trained, highly educated scientist really believe that 2.3 million tons of stone, some blocks weighing 70 tons, could have been transported and lifted by primitive methods? That seems improbable, though they have no compunction against lying to the public, writing textbooks and defending this theory against alternative theories. However, we must note that they will not subject themselves to the bottom-line test.Sumeria no earlier than 4000 BC. The theory does not permit an advanced civilization to have existed prior to that time. End of discussion. Archaeology and history lose their meaning without a fixed timeline as a point of reference.The biological sciences today are based on Darwinism.
The case of authorMichael Cremois well documented, and it also demonstrates how the scientific establishment openly uses pressure tactics on the media and government. His book Forbidden Archeology examines many previously ignored examples of artifacts that prove modern man’s antiquity far exceeds the age given in accepted chronologies.
We think it is incumbent upon any scientist to bear the burden of proof of his/her thesis; however, the social scientists who make these claims have never stood up to that kind of scrutiny. That is why we must suspect a conspiracy. No other scientific discipline would get away with bending the rules of science. All that Egyptologists have ever done is bat down alternative theories using underhanded tactics. It is time to insist that they prove their own proposals.
Why would scientists try to hide the truth and avoid any test of their hypothesis? Their motivations are equally transparent. If it can be proved that the Egyptians did not build the Great Pyramid in 2500 BC using primitive methods, or if the Sphinx can be dated to 9000 BC, the whole house of cards comes tumbling down. Orthodox views of cultural evolution are based upon a chronology of civilization having started in
Since the theory of “cultural evolution” has been tied to Darwin’s general theory of evolution, even more is at stake. Does this explain why facts, anomalies and enigmas are denied, suppressed and/or ignored? Yes, it does.
The examples which he and his co-author present are controversial, but the book became far more controversial than the contents when it was used in a documentary.
In 1996, NBC broadcast a special called The Mysterious Origins of Man, which featured material from Cremo’s book. The reaction from the scientific community went off the Richter scale. NBC was deluged with letters from irate scientists who called the producer “a fraud” and the whole program “a hoax”.
But the scientists went further than this–a lot further. In an extremely unconscionable sequence of bizarre moves, they tried to force NBC not to rebroadcast the popular program, but that effort failed. Then they took the most radical step of all: they presented their case to the federal government and requested the Federal Communications Commission to step in and bar NBC from airing the program again.
This was not only an apparent infringement of free speech and a blatant attempt to thwart commerce, it was an unprecedented effort to censor intellectual discourse. If the public or any government agency made an attempt to handcuff the scientific establishment, the public would never hear the end of it.
The letter to the FCC written by Dr Allison Palmer, President of the Institute for Cambrian Studies, is revealing:
At the very least, NBC should be required to make substantial prime-time apologies to their viewing audience for a sufficient period of time so that the audience clearly gets the message that they were duped. In addition, NBC should perhaps be fined sufficiently so that a major fund for public science education can be established.I think we have some good leads on who “the Brain Police” are. And I really do not think “conspiracy” is too strong a word–because for every case of this kind of attempted suppression that is exposed, 10 others are going on successfully.
We have no idea how many enigmatic artifacts or dates have been labeled “error” and tucked away in storage warehouses or circular files, never to see the light of day.
The way to get to utopia is to model your view of human nature and then invent a technology to control or direct that model — whether a political technology like the one Thomas Hobbes portrays in his Leviathan, a biological technology as in Aldous Huxley’s Brave New World, a psychological technology as in B. F. Skinner’s Walden Two, epistemo-technologies, as in Bacon’s The New Atlantis, information technologies as in Orwell’s 1984, or just plain old technology generally, as in H.G. Wells’ A Modern Utopia. I call these utopian visions “technologies” because they are deterministic in all senses of that word: systems that seek and believe in perfect control. When the human is inserted into the utopian system, the result is a feedback loop, in which the system encourages the “best” part and controls the “worst” part of human nature, while the human, in return, maintains the system with material, energy, information, flesh, and spirit.
In other words, the result of the inscription of a utopian vision onto a human is a cyborg: a natural organism linked for its survival and improvement to a cybernetic system. Of all the great utopianists, Sir Thomas More, Francis Bacon, Campanella, Restif de la Bretonne, Locke, Rousseau…, it is Thomas Hobbes in Leviathan (1651) who understands the essentially cyborg quality of utopia.
Seeing [that] life is but a motion of limbs, the beginning whereof is in some principal part within, why may we not say that all automata (engines that move themselves by springs and wheels as doth a watch) have an artificial life? For what is the heart but a spring, and the nerves but so many strings; and the joints but so many wheels giving motion to the whole body such as was intended by the Artificer? Art goes yet further, imitating that rational and most excellent work of nature, man. For by art is created that great Leviathan called a Common wealth or a State [in Latin, civitas] which is but an artificial man, though of greater stature and strength.
Scratch the model for a utopia and you get a blueprint of human nature. As we revise our technologic, different versions of utopia become imaginable, which in turn are fed by and feed into different versions of the human, which in turn are fed by and feed into new technologies, and so on, creating a feedback loop the byproduct of which is an ever more sophisticated version of the cyborg, whose generations can be measured by the turns of this spiralling loop.
The blueprint of human nature has always been subject to revision. But never as radically as now, when our own utopian technologies are physically transcribing themselves onto our bodies and re-creating the human in their own image, or forcing our evolution into what many have come to call the “posthuman” through a combination of mechanistic and genetic-biological manipulations. In short, the posthuman is the inscription of the ultimate controlling technology onto the human, the cybernetic technologies of selfhood, of mental identity, of cognition, of the mind, of intelligence itself, of communication, of language, and of The Code. To that extent, we are all cyborgs already, controlled by the systems we’ve embraced or which have embraced and defined us through our media, our computers, our systems of communication. For this reason, virtual reality, or cyberspace, is the perfect expression of postmodern trends.
A mysterious space visitor streaked past Earth at 21,000 mph yesterday. (In fact the object was moving slightly slower than the returning Apollo capsules did from the manned moon missions.)
Shuttling between the orbits of Mars and Venus, the vagabond swept within 76,000 miles of Earth at 7:46 a.m. EST.
Somehow the Mayan culture and Nostradamus missed predicting this one. The Earth-buzzing object, designated 2010 AL30, wasn’t discovered until January 10 by the LINEAR survey of MIT’s Lincoln Laboratories.
But speaking of doomsday predictions, what would have happened if the object had slammed into Earth yesterday? What would today’s headlines read?
It depends if the object is natural or manmade. Ian reported that some scientists think it might be the discarded rocket booster from the European Space Agency’s Venus Express.
Assuming it is an asteroid with the density of rock, it would be 30 feet across. As it plowed into our atmosphere, all of the asteroid’s kinetic energy would have been converted into light, sound, and heat under a crushing deceleration dozens of times the normal pull of gravity. The atmospheric stresses would probably have been severe enough to break up the asteroid. It would have momentarily blazed brighter than the sun as it unleashed as much energy as 30,000 tons of TNT exploding. That’s the same as exploding two Hiroshima-sized atom bombs.
Statistically, atmospheric explosions by falling debris should seriously damage or destroy a commercial airliner once every 50 years.
The Scale and Frequency Guide to Earth impacting Space Debris
Microscopic objects: interplanetary dust grains slow to a halt in the upper atmosphere and gently settle to the ground, depositing 120 tons per day as meteoric dust. (And I just washed the car!)
Pebble to baseball sized objects: This is the range for meteors or so-called “shooting stars.” They are heated by friction as they enter the atmosphere, become incandescent, and vaporize. The biggest in the range can momentarily become as bright as Venus.
Dining room table sized objects: These often fragment in the atmosphere and scatter pieces on the ground as meteorites. Meteors that blow apart lower in the denser atmosphere often emit sonic booms. Defense satellite data show that Earth collides with such objects several times a year. Statistically, at least one car per year should be hit by a meteorite. (And I just got a new paint job!)
Large building sized objects: These come along every century or two. An aerial disintegration and explosion would be powerful enough to level a major city. The Tunguska, Siberia fireball of 1908 was one such event.
Football-field sized objects: These visitors may come once every 1,000 year and unleash energies comparable to largest nuclear weapons. They will blast out mile-wide craters and burn everything within a few miles of the impact site.
Small town sized objects: These once in a million year visitors release energies comparable to thousands of large nuclear weapons all going off at once. They will blast out a crater over 10 miles across. All life within at least 100 miles of ground zero will be extinguished. Ejecta will devastate the landscape even farther beyond the crater.
City-sized objects: These are dinosaur-killer class asteroids, as recorded in the geologic strata from 65 million years ago. Their impact energies far exceed the total nuclear arsenal at the peak of the Cold War. The titanic blast will demolish an entire continent. Dust raised by the impact will have devastating global climatic effects and trigger mass extinctions. These impacts happen every 10 to 100 million years.
Large state-sized asteroids: Not to worry you “2012” soothsayers, this hasn’t happened in 4 billion years. The impact would vaporize enough rock to cover the earth, sterilize the surface and boil away much of the atmosphere.
If one considers the millions of years of pre-history, and the rapid technological advancement occurring now, if you apply that to a hypothetical alien race, one can figure the probabilities of how advanced the explorers will find them. The conclusion is “we will find apes or angels, but not men.”
Why? Consider the history of Planet Earth. Let the height of the Empire State building represent the 5 billion year life of Terra. The height of a one-foot ruler perched on top would represent the million years of Man’s existence. The thickness of a dime will represent the ten thousand years of Man’s civilization. And the thickness of a postage stamp will represent the 300 years of Man’s technological civilization. An unknown portion above represents “pre-Singularity Man”, the period up to the point where mankind hits the Singularity/evolves into a higher form/turns into angels. Say another dime. Above that would be another Empire State building, representing the latter 5 billion years of Terra’s lifespan.
If you picked a millimeter of this tower at random, what would you most likely hit? One of the Empire State buildings, of course. So,assuming only one civilization develops on a planet, chances are the first-in-scout starship Daniel Boone will discover mostly planets that are currently empty of alien civilizations (but they might have an almost 50% chance to discover valuable Forerunner artifacts or other paleotechnology).
As a matter of terminology, a long-extinct star faring alien civilization are commonly called “Forerunners”, “Precursors”, “Ancients”, “Elder race”, “Progenitors”, or “Predecessors”. Their thousand year old ruins are sobering, but their high-tech artifacts are generally far in advance of current tech levels and are of course both incredibly valuable yet incredibly dangerous. Archaeologists who stumble over such remains have a tendency to be killed by pirates, and their artifacts stolen.
If you only use the section with an alien civilization, you have a ruler and two dimes worth of apes and angels, and a postage stamp worth of near Human civilization. Ergo: apes or angels, but not men.
As a side note, one can use the time between apes and angels for the “average lifespan of a technological civilization”. Insert this into the Drake equation along with a few other guesses and you can calculate the average distance between alien civilization homeworlds. (and of course the distance between Terra and the closest aliens).
Consider the high improbability that any two Earth-like planets will form and evolve to the exact and ideal conditions that develop and support carbon-based life.
Consider also the number of mass extinctions that have occurred in Earth’s past. It is unlikely that the same number of these would occur on another Earth- like world at exactly the same time and with the exact same frequency.
Finally, consider the cultural developments in Earth’s history, and apply a few “What Ifs.” What if Democracy had never developed beyond the conceptual stage? What if Rome had never fallen? What if Columbus had never received any financial backing from the Spaniards? What if the Nazis had developed the atomic bomb first?
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Would any of one of these events have delayed or advanced human development by as much as 0.001%? One value given for the age of the Earth is 4.567 billion years. A +/- 0.001% change would set human evolution back by 4.567 million years (Apes), or advance it by 4.567 million years (Angels).
Thus, by “Apes & Angels” one could say that any two worlds that formed at exactly the same time, and that have had billions of years to go from dust to sentient life, could differ by as much as 9.134 million years in evolution!
A divergence of only 0.000001% would still separate the two extremes by 9.134 thousand years. With this value, one alien world could have a bronze-age culture (year = 2560 BCE), while another could be far ahead of our own, both culturally and technologically (year = 6574 CE). Maybe not “Apes & Angels” but perhaps “Spearchuckers & Supermen”?
[/SPECULATION]
My Example: The planet Earth will have a life-span of roughly ten billion years. Mankind (Homo sapiens) appeared on Earth approximately 100,000 years ago. The bronze age began about 5300 years ago. The Industrial Revolution began about 250 years ago.
When will we humans evolve into angels? Vernor Vinge thinks the Singularity will happen no later than the year 2030. But I’ll be generous and use 500 years from now, using John Barnes’ rule of thumb. How long will the angels last? No idea. For lack of anything else, let’s say 100,000 years from now, placing us current humans midway between apes and angels.
Now, assuming that the Daniel Boone only visits planets that be hosts to alien species, and assuming that each planet will only produce one alien species (which is a very questionable assumption), this means that the chance of discovering a living alien species is about 200,000/10,000,000,000 = 0.00002 = one chance in 50,000.
The poor Daniel Boone will on average have to visit fifty thousand planets in order to find one alien species. (Of course the Daniel Boone will probably be targeting planets about the same age as Earth and using other strategies to drastically reduce the number it will have to visit.)
Now, say that somehow the Daniel Boone manages to visit enough planets to discover 267 alien species. What level with they be at? Doing the math, 133 in 267 will be angels, 126 in 267 will be cave men, 7 in 267 will be on par with ancient Egypt, and only one in 267 will be a technological species. Keeping in mind that in this case, “technological” means it has technology ranging from steam power to something out of Star Wars (the 1760’s to the 2500’s).
The Daniel Boone will encounter 126 planets full of cave-man level aliens that they can play “Chariots of the Gods” with, and will have to avoid 133 planets with god-like species eager to put our intrepid explorers into giant petri dishes for their experiments with primitive life forms.
If these figures do not suit you, this is your opportunity to play with the various values until more reasonable numbers appear. But you will be forced to live with the implications of any values you change.
In those science fiction novels that care about technical details, there are some solutions mentioned. They all rely upon some method to start all the alien species in a stellar region simultaneously. This means that they will all develop at roughly the same rate, and encounter each other at roughly the same technological level. Solutions include postulating some alien race at the dawn of galactic history seeding planets, or disasters like gamma-ray bursters destroying all life in a galactic zone, forcing the planets to start re-evolving life starting at the same point in time.
I say “homeworlds” because they might have colonized nearby stars to form an empire. In this case the homeworld will probably be in the center of the empire’s sphere of influence. Therefore the closest aliens will be the average distance between minus the radius of their empire. Go to The Tough Guide to the Known Galaxy and read the entry “HOMEWORLD”
If you already have an idea of how close you want civilizations to be spaced, you work the Drake equation backwards. Keep altering the values until you get the spacing you want. But now you have to live with the consequences of those various values, and their implications.
It will be even worse if the average lifespan of a technological civilization is shorter than expected, due to premature death by nuclear holocaust or unexpected apotheosis by a VingianSingularity.
Just glancing though your section there, the key challenge for a lot of purposes is time scale — and oddly, it doesn’t have much to do with ship speed; an STL civilization might expand over the long haul nearly as fast as an FTL one.
The key issue – and this comes up in all sorts of contexts — is how long does it take for a planet to go from raw young colony to major world, the kind that could and might send out colonies of its own? This is the basic problem you have to solve for settings in which anyone has a space fleet of their own but Earth.
Let me try to put a few numbers on it.
The threshold for having a space fleet is arguably lower than for colonization, because a planet of 100 million people could probably maintain starships, but probably is not feeling a big population squeeze. To be sure, on some planets the habitable area will be pretty much filled, and even on the more earthlike ones the human presence is getting pervasive, so some impulse to colonize might be developing.
Whether a planet of 10 million people – the equivalent of a single large urban region — could realistically have a diversified enough economy to maintain and operate a fleet of starships seems a bit iffy, unless they are putting a massive effort into it, so massive that it may stunt their other prospects.
The most likely scenario for a world of 10 million people sending out a colony might be that they’ve decided their current home sux, and they’re going to try their shot at another one.
Looking at the other end, how many people for a viable colony. I’d say 10,000 at the low end, with 100,000 seeming a lot more comfortable. That’s the population of one semirural county. How many machine shops and such does it have, how much can they specialize for efficiency, and oh yeah, you need raw material, a mining sector and all that.
If you can’t make it you have to import it, paying starship freight instead of truck freight, and what have you got for sale? The market for colony-world curios is going to get crowded fast, and if you really do have something to sell, you’ll probably need more than a one-county economy to produce it in commercial quantities.
So I would say that you usually have to put 100,000 people onto a colony planet for it to thrive. Colonies with fewer than that can hang on, but if subsidies are cut off they may die off outright, or be stuck in a marginal existence; only lucky ones will overcome it and do okay.
For a colony to really go as a largely self-sufficient post industrial world it had better have on order of a million people — more or less the equivalent of Bakersfield and environs. I am certain that Australia has a Bakersfield, but I do not know what it is. Maybe our Oz contingent can inform us.
But once again, if they can’t make it or pay starship freight for it they do without it, and the equivalent of Bakersfield has a tough challenge producing nearly all the needs of post industrial civilization. And for exports it is good to have one sizeable airport that can double as the shuttle port and provide steady employment for a lot of the techs.
so hold your pitchforks. This is predicated on the 23rd century, or 28th or whatever, having about the same productive efficiencies of scale that we are used to. If you have got replicators where you shovel dirt in one end and get a washing machine or air car out the other, things are different. But you still need a wide range of human skills, very hard for small communities to provide, maintain, and keep active.
So maybe my figures could all be squeezed down by an order of magnitude, so that a colony of 10,000 is fairly viable, a colony of 100,000 can maintain a full industrial base, and one of a million people can keep its own starships in service. That helps for story settings, but you wouldn’t generally expect worlds like that to be active colonizers.
Finally, and most central to time scale, how fast do colony populations grow, either from immigration or birth rate? I would call a million emigrants from Earth each year a benchmark figure for large scale colonization. That’s several thousand people each day, one huge ship or several merely big ones, and it still takes a century of sustained effort to plant 100 colonies, each of a million people.
From the colony’s point of view, people are another expensive import, if you have to pay them to come. If they can afford a ticket and house stake they will only go to desirable colonies. If someone is paying to ship people to you, you may want to know why, because colonies could be a good place to dump dissidents, minor troublemakers, and similar riffraff.
On the export side, I’m more dubious of shipping off refugees, because by definition you’re dealing with lots of them, and shipping them all off world is horribly expensive. Much more so than just plucking the town crank and town pickpocket off the streets and getting them to volunteer for emigration.
But by and large you expect that mass colonization involves people who weren’t doing so great on Earth, because the supply of nut enthusiasts like people on this board who would actually like to colonize is limited, and a million people a year is a lot.
The other side of colonial growth is reproductive growth. Doubling the population each generation is about the historical sustained maximum. That corresponds to 10x per century, soDeseret World might go from 100,000 people to 10 million people in 200 years.
But even doubling per century is a pretty robust population growth rate. That’s roughly 1.2x per generation. Unless you’re growing ‘em in vats, about half the women are having three or four kids, and one way or another the society encourages and accommodates itself to this.
It’s no given that post industrial societies will generally have this population growth rate, though colony worlds may not follow the current trend in industrialized societies toward ZPG or even less.
If colony populations do tend to grow, I suspect the driving force is not the Heinleinian trope of ranchers with half a dozen marriageable — and “husband-high” — daughters, but the pervasive shortage of skilled specialists of all sorts. How this is transmitted to social attitudes I’m not sure, and no doubt can vary widely.
A colony with population doubling each century will go from 100,000 people to 10 million people in about 700 years, pushing us into the second half of the millennium.
Looking at it broadly, say that the age of colonization is around 2250-2350. That is a fairly common time frame for interstellar SF with a geocentric setting; (Star) Trek is vaguely in this era, AD2300 of course, and it’s implied by some of Heinlein’s interstellar stories.
After a century or so colonization from Earth sputters out, because all the low-hanging fruit has been plucked, and it is increasingly costly to reach virgin planets.
Emigration from Earth to the existing colonies can continue after that, but at some point the rate will likely fall. Successful colonies will no longer want people dumped on them, unsuccessful colonies can’t absorb them, so emigration falls to the level of people who can pay to go and want to go, or who the colonies are willing to pay for.
So. At some point around 2400, colonization has tapered off and emigration is tapering off. We can guess that there are at least a dozen or so full colony planets – if you can reach any you can probably reach about that many (and you need a good handful for a decent scenario).
The upward limit is about 100 or so true colony worlds, set – regardless of how many worlds are in reach of your FTL – by the postulated size of the colonization wave. A hundred million people, a hundred worlds – an average of about a million immigrants per colony, though the distribution may well be oligarchic by a power law, a handful of colonies getting a large share of total immigrants, growing to populations of up to a few tens of millions, while most have less than a million and kind of struggle along.
Beyond and between the colonies there may be planets never made into self-sustaining colonies, but remaining as outposts, and likely with some permanent populations. If someone pulls the plug on these, though, don’t miss the last bus out. Same with space stations and such.
As with the chronology, I think this is a fairly classical scale for a mid-interstellar setting — when there are already established colony worlds, that you can get to by starliner, not just outpost transport or even colonization ship.
There are enough worlds for a diverse interstellar setting, but few enough that people who deal with space, at least, will have some notion of them all as distinct places. (The way “Spain” conveys something to you, or “New Delhi,” but “Florianópolis” probably does not.
A few of these colonies already in 2400 have upwards of 10 million people and some potential to colonize themselves, but these were the immigration magnets, so they probably still feel short-handed if anything, not inclined to send lots of people off.
It will take 200 or 300 years for smaller colonies with rapid population growth rates to start pushing up into the 10 million population range, and might have the impulse and capability to colonize. But it might take closer to 500 years for a substantial number of the original colonies to have much motivation to colonize.
The early goers, though, will have filled in the next layer of easy pickings. Here is where your FTL really matters – whether you can light off freely into the vastness to hunt for a suitable planet, or are constrained by a colonization sphere that is starting to grow again.
But broadly speaking, it seems that secondary colonization couldn’t be expected in any serious way until sometime well after 2500, and perhaps not in a big way till sometime around 2700-3000.
An interstellar domain can have no definite borders; stars are scattered too thinly, their types too intermingled. And there are too many of them. In very crude approximation, the Terrestrial Empire was a sphere of some 400 light-years diameter, centered on Sol, and contained an estimated four million stars. But of these less than half had even been visited. A bare 100,000 were directly concerned with the Imperium, a few multiples of that number might have some shadowy contact and owe a theoretical allegiance.
Consider a single planet; realize that it is a world, as big and varied and strange as this Terra ever was, with as many conflicting elements of race and language and culture among its natives; estimate how much government even one planet requires, and see how quickly a reign over many becomes impossibly huge.
Then consider, too, how small a percentage of stars are of any use to a given species (too hot, too cold, too turbulent, too many companions) and, of those, how few will have even one planet where that species is reasonably safe. The Empire becomes tenuous indeed.
And its inconceivable extent is still the merest speck in one outlying part of one spiral arm of one galaxy; among a hundred billion or more great suns, those known to any single world are the barest, tiniest handful.
When it comes to weapons, it looks like three main types: beam weapons, kinetic weapons, and missiles. Beam weapons are lasers and particle beams. Kinetic weapons are coilguns, railguns, and shrapnel weapons. Missiles are, well, missiles. Ken Burnside compared it to a policeperson armed with a service revolver, a shotgun, and a police dog. The revolver (beam weapon) cannot be dodged or outrun, but can miss. The shotgun (kinetic weapon) is more likely to hit, but with reduced lethality. The dog (missile) can be dodged or outrun (or shot, that would correspond to point defense), but the blasted thing will chase you, and will always hit unless you actively prevent it.
(Holger Bjerre begs to differ. He points out that kinetic weapons are less likely to hit since it can be dodged, beam weapons lose lethality with range just like shotguns, and kinetic weapons do not lose lethality with range just like revolvers. Well, no analogy is perfect…)
Dave Bryant has his own analysis of spacecraft weaponry here. I’m not sure I agree with all of it, so do your own research.
One of the problems with figuring out how ships are going to fight in space (assuming that we have ships in space, which isn’t as likely as I wish; and, that we’re still fighting when we get there, which is unfortunately more probable) is that there are a lot of maritime models to choose from.
It’s also true that some of the maritime models came from very specialized sets of circumstances; and a few of them weren’t particularly good ideas even in their own time.
And it’s also true that some of the writers applying the models have a better grasp of the essentials than others. For example, I recall two essays which were originally published about fifty years ago in Astounding.
In the first of the essays (“Space War”, Astounding Science-Fiction, Aug 1939), Willy Ley, a very knowledgeable man who had been involved with the German rocket program, proved to my satisfaction that warships in space would carry guns, not missiles, because, over a certain small number of rounds, the weight of a gun and its ammunition was less than the weight of the same number of complete missiles. The essay was illustrated with graphs of pressure curves, and was based on the actual performance of nineteenth-century British rocket artillery (“the rockets’ red glare” of Francis Scott Key).
As I say, the essay was perfectly convincing … until I read the paired piece by Malcolm Jameson.
Jameson’s qualifications were relatively meager. Before throat cancer force him to retire, he’d been a United States naval officer — but he was a mustang, risen from the rank, rather than an officer with the benefit of an Annapolis education. For that matter, Jameson had been a submariner rather than a surface-ship sailor during much of his career. That was a dangerous specialty — certainly as dangerous a career track as any in the peacetime navy — but it had limited obvious bearing on war in vacuum.
Jameson’s advantage was common sense. He pointed out (very gently) that at interplanetary velocities, a target would move something on the order of three miles between the time a gun was fired and the time the projectile reached the end of the barrel.
The rest of Jameson’s essay discussed tactics for missile-launching spaceships — which were possible, as the laws of physics proved gun-laying spaceships were not. Ley could have done that math just as easily. It simply hadn’t occurred to him to ask the necessary questions.
Here are some weapons list, you must need if you are involved in interplanetary space wars:
I. Weapons systems.
A. Banks. Beams of directed particles fired at a target.
1. Electromagnetic beams. Beams of photons (note this includes lasers, masers, xasers, gasers, etc.).
a. continuous
b. pulsed
c. single-shot submunition
2. Particle beams. Beams of high-energy charged particles (such as protons).
a. continuous
b. pulsed
c. single-shot submunition
B. Cannon. Unguided projectiles directed at a ship target.
1. Kinetics. Mere slugs fired at a target with no explosive capability.
2. Shells. Unguided projectiles fired at a target which detonated with a proximity fuse and a conventional warhead.
C. Tubes. Guided projectiles directed at a ship target.
1. Missiles. Guided projectiles with a proximity fuse. Has higher acceleration than average target ship.
2. Torpedoes (AKV). Guided projectiles with a proximity fuse. Has lower acceleration than average target ship.
3. Rockets. Dumbfire missiles, which only accelerate in the direction they were fired.
D. Releases. Guided projectiles directed at a planetary target.
1. Atmospherics. Projectiles designed to reenter an atmosphere and detonate over a ground target.
2. Biologics. Atmospherics with a biological warhead.
3. Kinetics. No warhead. Does damage with kinetic energy, by large velocities or large mass, or both.
E. Layers. Latent projectiles merely dropped with only a slightly different speed from the firing ship.
1. Mines. Conventional warheads which drift in orbit and a proximity fuse which then accelerate toward their target and detonate.
II. Active defense systems.
A. Point defense. Smaller-sized kinetics, missiles, and beams directed at incoming weapons.
B. Minesweepers. Point defense designed to eliminate mines.
C. Charge dampener (?). Anticharge systems designed to reduce the damage caused by particle beams.
E. Nanotechnology dynamic armor repair.
III. Passive defense systems.
A. Armor.
1. Ablative armor.
2. Reflective armor. Armor designed to deflect beam weapons, even as it is worn away.
B. Shields. [These are pretty hard to classify, since they're the only broad class of system that is hard to explain through current science.]
A. Electronic countermeasures. Electronic equipment designed to foil weapon targeting systems.
B. Decoys. Launched devices designed to foil incoming weapons with false signals.
1. Electromagnetic decoys. Decoys which emit misleading electromagnetic signals.
C. Jammer. Electronic equipment designed to foil broadband electromagnetic signals.
This scheme was created by Timothy Miller (Cerebus), and contains some modifications by Erik Max Francis:
1 Deployment: How the weapons system is initially launched (fired). Note: Do not confuse this description with Guidance.
1a Active: These weapons deploy themselves upon activation, with the propulsive mechanism integral to the unit; as a class, this includes commonly-termed missiles and torpedoes.
1b Passive:These weapons are deployed by an external device, launcher or other means.
1b1 Gun fired: Deployed by common explosives, as through an artillery piece.
1b2 Railgun launched: Deployed by electromagnetic launcher, typically to much higher velocities than possible by Gun-fired or other methods; as such deserves a separate description.
1b3 Dropped: Deployed by simply leaving the weapon behind you, without appreciable external impetus.
1b4 Hand launched: Thrown, hurled, kicked or otherwise deployed by physical exertion.
1c Lay in wait: These are fired passively, and activated when they in a given proximity to their target (i.e., “mines”)
2 Guidance: Describes methods of an individual weapon achieving its objective.
2a Dumb: No post-deployment guidance. Either you aimed right or you didn’t.
2b Smart: Capable of post-deployment guidance of any type (glide, thrust, etc.)
2b1 External: Guided by external sensors and control.
2b1a Wire guided: Guidance received through trailing wire. Limited in range, but not susceptible to interference.
2b1b Signal guided: Less limited in range, but more susceptible to interference.
2b2 Internal: Guided by internal sensors.
3 Kill Type: How the weapons system damages the target.
3a Kinetic: These weapons carry no warheads, relying on impact energy alone to damage the target.
3a1 Single warhead
3a2 Scattershot: Weapon segments into shrapnel upon deployment. 3b1c types on the other hand delay segmentation until activation
3b Explosive: These weapons carry explosives of varying types, and rely on on- or near-target detonation to damage the target.
3b1 Chemical: Common (or uncommon) chemical explosives.
3b1a Blast: Relies on blast effects.
3b1b Armor piercing: Self-explanatory.
3b1c Shrapnel: Weapons that intentionally shatter or otherwise scatter projectiles to incapacitate or kill. This can be anything from flechette-scattering missiles to hand grenades.
3b2 Nuclear: Self-explanatory, includes both fission and fusion devices.
3b3 Antimatter
3c Directed Energy: These weapons transfer energy directly to the target, at range.
3c1 Electromagnetic: Lasers and kin (masers, grasers, etc.)
3c1a Submunitions: Bomb-pumped lasers
3c2 Particle beam: Charged or neutral particles, not to be confused with small-sized railgun-fired projectiles. Typically limited to atomic or sub-atomic particles.
3d Chemical: Anti-personnel weapons that attempt to poison the biological processes of the target to incapacitate or kill.
3e Biological: Anti-personnel weapons that attempt to infect the target and incapacitate or kill.
3f Radiological: Anti-personnel weapons that attempt to expose the target to incapacitating amounts of radiation.
4 Acquisition: Describes methods of an individual weapon detecting and targeting, its objective.
4a Active: Weapon emits radiation to detect targets (e.g., radar).
4b Passive: Weapon passively scans for target emissions (e.g., infrared)
4c Illumination: Weapons passively scans for an illumination signature painted on target by a third object.
4d Command : Weapon is issued an attack command by the controlling ship.
5 Trigger: Generally only for warheads, determines what causes weapon to detonate.
5a Command: Detonated by command from controlling ship.
5b Impact: Detonated by contact with target.
5c Proximity: Detonates within predetermined range of the target.
5d Timed: Detonates after a pre-determined time.
5e Check-in: Detonates after the inability to contact a friendly ship after a predetermined period of time.
The great silence (i.e., absence of SETI signals from alien civilizations) is perhaps the strongest indicator of all that high relativistic velocities are attainable and that everybody out there knows it.
The sobering truth is that relativistic civilizations are a potential nightmare to anyone living within range of them. The problem is that objects traveling at an appreciable fraction of light speed are never where you see them when you see them (i.e., light-speed lag). Relativistic rockets, if their owners turn out to be less than benevolent, are both totally unstoppable and totally destructive. A starship weighing in at 1,500 tons (approximately the weight of a fully fueled space shuttle sitting on the launchpad) impacting an earthlike planet at “only” 30 percent of lightspeed will release 1.5 million megatons of energy — an explosive force equivalent to 150 times today’s global nuclear arsenal… (ed note: this means the freaking thing has about nine hundred mega-Ricks of damage!)
I’m not going to talk about ideas. I’m going to talk about reality. It will probably not be good for us ever to build and fire up an antimatter engine. According to Powell, given the proper detecting devices, a Valkyrie engine burn could be seen out to a radius of several light-years and may draw us into a game we’d rather not play, a game in which, if we appear to be even the vaguest threat to another civilization and if the resources are available to eliminate us, then it is logical to do so.
The game plan is, in its simplest terms, the relativistic inverse to the golden rule: “Do unto the other fellow as he would do unto you and do it first.”…
When we put our heads together and tried to list everything we could say with certainty about other civilizations, without having actually met them, all that we knew boiled down to three simple laws of alien behavior:
1. THEIR SURVIVAL WILL BE MORE IMPORTANT THAN OUR SURVIVAL.
If an alien species has to choose between them and us, they won’t choose us. It is difficult to imagine a contrary case; species don’t survive by being self-sacrificing.
2. WIMPS DON’T BECOME TOP DOGS.
No species makes it to the top by being passive. The species in charge of any given planet will be highly intelligent, alert, aggressive, and ruthless when necessary.
3. THEY WILL ASSUME THAT THE FIRST TWO LAWS APPLY TO US.
…
Your thinking still seems a bit narrow. Consider several broadening ideas:
Sure, relativistic bombs are powerful because the antagonist has already invested huge energies in them that can be released quickly, and they’re hard to hit. But they are costly investments and necessarily reduce other activities the species could explore. For example:
Dispersal of the species into many small, hard-to-see targets, such as asteroids, buried civilizations, cometary nuclei, various space habitats. These are hard to wipe out.
But wait — while relativistic bombs are readily visible to us in foresight, they hardly represent the end point in foreseeable technology. What will humans of, say, two centuries hence think of as the “obvious” lethal effect? Five centuries? A hundred? Personally I’d pick some rampaging self-reproducing thingy (mechanical or organic), then sneak it into all the biospheres I wanted to destroy. My point here is that no particular physical effect — with its pluses, minuses, and trade-offs — is likely to dominate the thinking of the galaxy.
So what might really aged civilizations do? Disperse, of course, and also not attack new arrivals in the galaxy, for fear that they might not get them all. Why? Because revenge is probably selected for in surviving species, and anybody truly looking out for long-term interests will not want to leave a youthful species with a grudge, sneaking around behind its back…
I agree with most parts of points 2, 3, and 4. As for point 1, it is cheaper than you think. You mention self-replicating machines in point 3, and while it is true that relativistic rockets require planetary power supplies, it is also true that we can power the whole Earth with a field of solar cells adding up to barely more than 200-by-200 kilometers, drawn out into a narrow band around the Moon’s equator. Self-replicating robots could accomplish this task with only the cost of developing the first twenty or thirty machines. And once we’re powering the Earth practically free of charge, why not let the robots keep building panels on the Lunar far side? Add a few self-replicating linear accelerator-building factories, and plug the accelerators into the panels, and you could produce enough anti-hydrogen to launch a starship every year. But why stop at the Moon? Have you looked at Mercury lately? …
Dr. Wells has obviously bought into the view of a friendly galaxy. This view is based upon the argument that unless we humans conquer our self-destructive warlike tendencies, we will wipe out our species and no longer be a threat to extrasolar civilizations. All well and good up to this point.
But then these optimists make the jump: If we are wise enough to survive and not wipe ourselves out, we will be peaceful — so peaceful that we will not wipe anybody else out, and as we are below on Earth, so other people will be above.
This is a non sequitur, because there is no guarantee that one follows the other, and for a very important reason: “They” are not part of our species.
Before we proceed any further, try the following thought experiment: watch the films Platoon and Aliens together and ask yourself if the plot lines don’t quickly blur and become indistinguishable. You’ll recall that in Vietnam, American troops were taught to regard the enemy as “Charlie” or “Gook,” dehumanizing words that made “them” easier to kill. In like manner, the British, Spanish, and French conquests of the discovery period were made easier by declaring dark- or red- or yellow-skinned people as something less than human, as a godless, faceless “them,” as literally another species.
Presumably there is some sort of inhibition against killing another member of our own species, because we have to work to overcome it…
But the rules do not apply to other species. Both humans and wolves lack inhibitions against killing chickens.
Humans kill other species all the time, even those with which we share the common bond of high intelligence. As you read this, hundreds of dolphins are being killed by tuna fishermen and drift netters. The killing goes on and on, and dolphins are not even a threat to us.
As near as we can tell, there is no inhibition against killing another species simply because it displays a high intelligence. So, as much as we love him, Carl Sagan’s theory that if a species makes it to the top and does not blow itself apart, then it will be nice to other intelligent species is probably wrong. Once you admit interstellar species will not necessarily be nice to one another simply by virtue of having survived, then you open up this whole nightmare of relativistic civilizations exterminating one another.
It’s an entirely new situation, emerging from the physical possibilities that will face any species that can overcome the natural interstellar quarantine of its solar system. The choices seem unforgiving, and the mind struggles to imagine circumstances under which an interstellar species might make contact without triggering the realization that it can’t afford to be proven wrong in its fears.
Got that? We can’t afford to wait to be proven wrong.
They won’t come to get our resources or our knowledge or our women or even because they’re just mean and want power over us. They’ll come to destroy us to insure their survival, even if we’re no apparent threat, because species death is just too much to risk, however remote the risk…
The most humbling feature of the relativistic bomb is that even if you happen to see it coming, its exact motion and position can never be determined; and given a technology even a hundred orders of magnitude above our own, you cannot hope to intercept one of these weapons. It often happens, in these discussions, that an expression from the old west arises: “God made some men bigger and stronger than others, but Mr. Colt made all men equal.” Variations on Mr. Colt’s weapon are still popular today, even in a society that possesses hydrogen bombs. Similarly, no matter how advanced civilizations grow, the relativistic bomb is not likely to go away…
We ask that you try just one more thought experiment. Imagine yourself taking a stroll through Manhattan, somewhere north of 68th street, deep inside Central Park, late at night. It would be nice to meet someone friendly, but you know that the park is dangerous at night. That’s when the monsters come out. There’s always a strong undercurrent of drug dealings, muggings, and occasional homicides.
It is not easy to distinguish the good guys from the bad guys. They dress alike, and the weapons are concealed. The only difference is intent, and you can’t read minds.
Stay in the dark long enough and you may hear an occasional distance shriek or blunder across a body.
How do you survive the night? The last thing you want to do is shout, “I’m here!” The next to last thing you want to do is reply to someone who shouts, “I’m a friend!”
What you would like to do is find a policeman, or get out of the park. But you don’t want to make noise or move towards a light where you might be spotted, and it is difficult to find either a policeman or your way out without making yourself known. Your safest option is to hunker down and wait for daylight, then safely walk out.
There are, of course, a few obvious differences between Central Park and the universe.
There is no policeman.
There is no way out.
And the night never ends.
Bill Seney points out a slight flaw in the above argument:
Attacking with relativistic rockets may be a good idea if there are only two technological species, but if there are two then it seems to me that it is likely there will be more. Using a relativistic rocket to destroy a planet will reveal your position AND indicate that you are hostile to any possible third race that is out there.
To extend the Central Park analogy, the muzzle flash when you fire off your gun reveals your position and identifies that you are hostile to anyone else out there.
With all this frightfulness flying at your ship, you’d want some kind of defense, besides just hoping they’ll miss. As mentioned 
This is also why those compartments would be buried as deep inside the ship as possible. No sense in making things easy for your enemy. True, on modern wet navey warships bridges are still mainly at the highest point of the ship, but that’s mainly to facilitate visual tracking and identification. In space, you cannot see the enemy with the naked eye anyway, so you might as well put your command centers where the enemy has to destroy the entire ship to get at it. 
The glow of methane has been detected in the atmosphere of Jupiter-sized alien planet orbiting close to its parent star.
In order to understand this evidence, let’s think about how a train sounds to a person standing on the platform. An arriving train makes a noise that starts low and gets higher pitched as the train approaches the listener, sounding like oooooohEEEEEEEE. A departing train makes a noise that gets lower pitched as the train goes away from the listener, sounding like EEEEEEEEoooooooh. This change in the sound of the pitch of the train noise depending on whether it is arriving or departing the listener is called the Doppler shift.
Similarly, for marine creatures that have a need for speed, the laws of hydrodynamics favor being long, thin, and oh-so-streamlined. Convergent evolution has ensured that barracudas are shaped like dolphins, even though the former are fish and the latter are mammals. Being built like a torpedo just works better.
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“Arrgh. You guys suck all the fun out of life! It’s a GAME, dammit!”
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