Beware of Microscopic Aliens: They may wipe us out!
September 1, 2010 7 Comments
Asteroids and cometary impact have ever posed threat to species. Most of us generally believe that such impacts may prang Earth since they have very large amount of kinetic energy, more than any nuclear explosion to the date. Imagining the devastating power of such heavenly impacts is not very hard, just remember the Tanguska Valley impact. The real threat might not be what is observable but that real threat could be microscopic. Yea, microbes may wipe us out. Microbes have extreme survivability tactics as I’ve written in my earlier article “Why Panspermia is Even More Plausible?” There are various mechanisms by which microorganisms are able to survive extreme physical conditions, likely to be associated with ejection into space. Bacteria and Archaea are small and typically range in size from 0.3 – 2 μm. Also in some environments there can be considerable population density (estimates of surface and subsurface population densities typically range from 101– >108/ g rock or soil. The small size and high numbers of microorganisms can result in the possibility of some being shielded and buffered in a protective, insulated microenvironment, during the catastrophic events and energy associated with impact-associated ejection into space. Other issues related to microbial survival during ejection is the shape and structure of the cell wall of bacteria. The spherical shape of many organisms, such as Staphylococcus sp.and spores produced by Bacillus and Clostridium sp.,has been associated with heightened resistance to shearing. Peptidoglycan, the main structural component of the bacterial cell wall, is very strong with estimates of its strength and elasticity surpassing steel. In many microbiology laboratories, bacteria are routinely harvested from liquid suspensions by centrifugation at a relative force sometimes approaching or exceeding 10,000 x gravity. Most bacteria, harvested in this fashion remain viable due to the strength of the peptidoglycan cell wall component. In contrast other biological entities, including human blood cells (erythrocytes) that are not protected by peptidoglycan, are broken (lysed) at much lower speeds (above 2000 x gravity).
Bacteria have a number of mechanisms by which they are able to resist and protect themselves against radiation and heat. When compared to mesophilic bacteria (that typically live between 20-40°C), thermophilic bacteria (optimum growth can exceed 100°C) have greatly enhanced protein and nucleic acid stability. These mechanisms include an increased cross-linking of proteins and altered DNA structure. When growing bacteria are subjected to temperatures approaching their upper growth range, cellular damage and death can arise from protein misfolding (denaturation), a loss of membrane integrity and DNA damage. Bacteria, including thermophiles, have a number of stress responses, including producing a variety of heat shock proteins. Early studies showed that bacteria such as Escherichia coli,expressed a number of heat shock genes when they approached their maximum growth temperature; and that bacteria defective in these genes had reduced thermal tolerance. Several heat shock genes encode the synthesis of a number of accessory proteins called chaperones.
This is not enough for microscopic alien invaders to ensure their survival. If somehow, these intruders reached here they may not be able to survive the impact. If you thinking in that way, might you be wrong. Atmospheric passage and impact yield many of the same stresses (heat, gravity, shear forces) as those experienced during entry into space. Through a series of planned and accidental events, there are several studies that have directly addressed microbial survival during this phase of panspermia. In one study (Horneck et al., 2001), spores from the bacterium, Bacillus subtilis,were placed between quartz plates and subjected to an explosion-induced, transient shock pressure of 32 GPa. Under these conditions, which mimic those of meteorite impact on Mars, a small number of spores survived (estimated survival rate was 10-4). In a second study (Burchell et al., 2001), Rhodococcus, a genus of non-spore forming bacteria, were attached to a projectile (bullet) that was then fired from a gun onto a target of growth media. Bacterial survival was also noted when spores were placed onto the ablative heat shield of a spacecraft, and exposed to heat during reentry.
Now it may seem astonishing that how could a bacteria or virus wipe us out? Well, it need not anymore explanation. What if such alien cometriders have toxic genes of some sort, which may innoculate their genes into us? Significantly we can’t refute the possibility that there microscopic creatures may also cause malfunctioning in our genes which would led to a rapid mutation, a scenario which was well portrayed in a hollywood movie(Resident Evil).
Changes in DNA caused by mutation can cause errors in protein sequence, creating partially or completely non-functional proteins. To function correctly, each cell depends on thousands of proteins to function in the right places at the right times. When a mutation alters a protein that plays a critical role in the body, a medical condition can result. A condition caused by mutations in one or more genes is called a genetic disorder. Some mutations alter a gene’s DNA base sequence but do not change the function of the protein made by the gene. Studies of the fly Drosophila melanogaster suggest that if a mutation does change a protein, this will probably be harmful, with about 70 percent of these mutations having damaging effects, and the remainder being either neutral or weakly beneficial. However, studies in yeast have shown that only 7% of mutations that are not in genes are harmful.
If a mutation is present in a germ cell, it can give rise to offspring that carries the mutation in all of its cells. This is the case in hereditary diseases. On the other hand, a mutation may occur in asomatic cell of an organism. Such mutations will be present in all descendants of this cell within the same organism, and certain mutations can cause the cell to become malignant, and thus causecancer. Often, gene mutations that could cause a genetic disorder are repaired by the DNA repair system of the cell. Each cell has a number of pathways through which enzymes recognize and repair mistakes in DNA. Because DNA can be damaged or mutated in many ways, the process of DNA repair is an important way in which the body protects itself from disease.
So what if these alien microbes are going to reprogramme our DNA? Even a single link breaking may cause some serious problems like malfunctioning of mind or extreme brutality(as portrayed in ‘The Hill Have Eye’] or anything else that could easily wipe us out more likely it would work as a bioweapon of some sort. A respected regular reader of WeirdSciences( An ‘ideaman’) Mr. Robert Schreib Jr. has pointed this scenario out in this comment.
Well, technically, having ETs clone human beings from a DNA capsule send into deep space would not constitute a valid first contact. The space probe with the DNA capsule should have some kind of super condensed computer memory to also send out the culture and historical information of being Human. A cloned human being in an alien world would not successfully convey what being Human IS to such aliens if he’s berift of the tons of culture that makes up your psyche. By the way, this concept was explored in the SF/Horror movie “Species”, but in that example, the DNA capsule was NOT that of an Alien species, but rather, a ‘WarMute’ genengineered entity comprised of diverse species, designed to be a killing machine that would have to mate with a local species to acquire the immune system for Earthy germs to then impart that to its offspring to destroy all humans on Earth. This unexplored plotline of that movie was that the aliens intended to conquer Earth with a fake DNA capsule like that, since ultra-tech weapons like atomic bombs, etc., would render the world inhabitable, so a kind of BioWeapon like this was send ahead of their advancing fleet, which would have a method of exterminating the hyper-aggressive ‘WarMutes’ through a weakness in their genetic code, so they could simply move in. Such hyper-aggressive predators make lousy scientists, so such an alien species would never have developed interstellar communication or interstellar transportation, so what they send in the radio signal was a super con game to trick the Humans or other sentient species into creating their own Waterloo so they could later acquire the prime real estate of a planet with a livable biosphere, the actual aliens were NOT that ‘species’ at all.
The nomadic aliens of Hawking may also choose such types of microscopic WarMutes, which would eventually make this planet habitable for them. That’s why we shouldn’t ignore such possibility. They might poke holes into our security system!!