Mars Mysteries and Need of Human Exploration

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Mars has been a mystery from a longtime ever since we have started to envision life thereon the Mars. Here is an excellent article from Markus Hotakainen, explaining the necessity of human exploration to Mars.

By Markus Hotakainen

1. Introduction

Until now Mars probes, orbital or vehicular, have been controlled by a combination of onboard software and radio communication with Earth-based humans. The main focus of interest has been the geological character of the planet (Levine et al., 2010a,b). However, there are many unexplained anomalies which are also deserving of attention and the close inspection of trained teams of astronauts.

The geological processes which characterize Mars are similar to and familiar from Earth (Levine 2010a,b). The principle of the past being the key to the present is applicable on the large scale. With a surface area similar to that of all the continents of Earth and a readily observable geological record of billions of years, Mars is a treasure-trove for planetary research, both of the planet itself, with relation to Earth, and in connection with the origin and evolution of the Solar System as a whole.

However, the exploration of Mars has to take into account the fact that during most of its evolution the conditions have been crucially different from those of the ancient and present-day Earth, which means similar processes could have led to different outcomes.Indeed, it is not just geology and biology, but the fact there are many unexplained Martian anomalies which require trained field scientists. For example, there is a wealth of enigmatic features on Mars defying any simple and straight-forward explanations. Many of these features will keep their secrets until human presence. Even the most sophisticated robotic probes with most advanced artificial intelligence lack – at least for the moment – the ingenuity and creativity of the human mind.

Thus the next step in the exploration of our planetary neighbor, should be a human mission to Mars and the landing a human crew, whose observations will certainly go beyond questions of geology but will also seek to determine whether life in any form exists on the planet today, or has existed in the past. Recent discoveries in the biological sciences have conclusively demonstrated that living organisms are capable of surviving in extreme conditions, and this means we cannot rule out the possibility that some form of organic life exists on Mars even in the conditions that prevail today. In terms of a search for evidence, there are a number of intriguing candidates for a landing site and base camp. Such sites would include proximity to water in the form of ice, which exists at the poles and also likely within the confines of some craters; all of which may harbor life.

Consequently exploring the anomalies of Mars could potentially give new insight into the geological and biological history of Mars and Earth. However, this would require human presence, as advocated by astronauts Dr. Edgar Mitchell (Mitchell & REF) and Dr. Harrison Schmitt (2010). Astronaut Schmitt is a trained geologist and the last man to step upon the surface of the Moon and he argues that it is imperative that field geologists accompany the first astronauts to Mars (Schmitt 2010). It is because of this astronaut geologist, and the human presence on the Moon, that the Apollo program contributed to many important discoveries giving clues to the birth and evolution of our cosmic companion.

Tracks to be followed. Robotic rovers – Sojourner, Opportunity, and Spirit – have paved a way to manned exploration of Mars. Credit: NASA/JPL/Cornell

2. Wet Mars

One of the most intriguing questions in the study of Mars has been and still is the existence of water. It is the most important substance making the difference as well as the similarity between Mars and Earth. The currently cold and arid Mars has experienced a period (or periods) of warmer and wetter climate with a considerably thicker atmosphere (Morris et al. 2010).

The images acquired with the high-resolution cameras of several probes launched during the past decade and a half – Mars Global Surveyor, Mars Odyssey, and Mars Reconnaissance Orbiter of NASA, and Mars Express of ESA – and the research conducted on the surface with the rovers – Sojourner, Opportunity, and Spirit – have proved that there has been water on the surface of Mars: lots of water (Carter et al. 2010; Di Achille 2010). And recent studies of the carbon and oxygen isotopes of the atmospheric CO2 suggests that there has been low-temperature interaction between water and rocks throughout the Martian history (Niles et al. 2010).

The surface of Mars is covered with different kinds of signatures of past water from narrow gullies on the walls of craters and slopes of hills and dunes through dried river beds and valleys carved by water to vast, smooth areas reminiscent of ocean floors. However, whether all of these formations are due to water (or ice) is still a matter of dispute, and other explanations like cryoclastic phenomena and gas-supported density flows have been brought forth (Hoffman 2000).

On the pole-facing slopes of the dunes in Russell Crater on the southern hemisphere of Mars there are narrow gullies side by side. Credit: NASA/JPL/University of Arizona

 

In many cases the surface anomalies – just like the more ordinary features – are seemingly the result of flowing water or melting ice, coupled with perhaps tricks of light and shadow and the propensity of the human imagination to conjure forth not just what is, but what might be. However, dismissing these anomalies as illusions or to assume they are the result of natural geological forces, is not in the spirit of science. Assumptions, be they pro or con, are not the same as facts. Rather, these surface anomalies require serious consideration and investigation which in turn would lead to the advancement of science, and lead to a greater understanding of planetary geology and the cause and origins of these anomalies.

3. Martian Arctic Ocean

The most prominent anomaly of Mars is the dichotomy between the northern and southern hemispheres. The southern highlands are covered with craters of all sizes, the northern lowlands are exceptionally flat and smooth. There is also an average difference of 4 kilometers in their elevations (Kiefer, 2008).

The highland-lowland dichotomy boundary of Mars is at most places – like in this area near Medusa Fossae – very apparent. Credit: ESA/DLR/FU Berlin (G. Neukum)

 

One of the theories is that there had been a vast Martian ocean covering most of the northern hemisphere. An ocean of Martian water would explain the smoothness. However, if there had been a Northern ocean, then where are the ancient shorelines? Shorelines should be evident at the borderline between the highlands and the lowlands. Although many have claimed to have detected these palaeoshorelines (Parker et al. 1993), these claims are in most cases controversial to say the least. If there had been ancient oceans, perhaps the shorelines have disappeared after being blanketed by later sedimentation. Or perhaps the failure to find conclusive evidence is due to the insufficient resolution of the imaging instrumentation of the probes. Trained field observers, could provide the answers.

The existence of an ancient ocean is further implied by the distribution of ancient deltas dilineating the margins of the northern lowlands. The level of these deltas is consistent with the possible palaeoshorelines indicated by the analysis of other morphological and topographical features, as well as the distribution and age of valley networks on the surface of Mars (Di Achille 2010).

Also the recent detection of hydrated silicates in the northern plains indicates a past presence of large amounts of water. The silicates have been known to exist on the southern highlands implying wet conditions early in the history of Mars, but now the same goes with the northern highlands. The ancient deposits of these hydrated silicates, being mostly phyllosilicates, excavated at places by impact cratering, are covered with hundreds of metres of later sedimentation (Carter et al. 2010).

Perhaps the answers concerning the existence of the ancient ocean could be obtained by sophisticated high-resolution cameras and deep-range radars onboard an orbiting craft. However, these answers may not be obtained without in-situ exploration, including deep drilling, which would be difficult to accomplish without human presence.

Finding a landing site with the highest potential to give an answer to this question on the existence of an ancient sea might also prove difficult. The borderline between the highlands and lowlands is at many places a very steep slope making it unsuitable for landing a manned craft. However, there is an area with not only an appropriate location, but a wealth of enigmatic features.

4. Cydonian Complex

The first feature to arouse the interest of both the scientific community and the general public was the detection of a “face-like” anomaly in the area known as Cydonia, a plain in a transitional region between heavily cratered southern highlands and the smooth northern lowlands; the so called “Face of Mars”. It was photographed by the Viking 1 Orbiter in July 1976 while making detailed imaging for the selection of the landing site for the Viking 1 Lander.

The unusual mesas of the Cydonia region has led to wild speculation on their origin. The infamous “Face of Mars” is near the lower right-hand corner of this image. [Credit: Mars Express/ESA

The image of the “Face” gained immediately great publicity and a keen interest in, along with various speculations on, the origin of the familiar looking formation. There are strong advocates for the interpretation that this feature with a length of 2,5 kilometres and a height of 250 metres is artificial, being some kind of a vast monument or perhaps a cenotaph. Later images taken by various orbiters having instruments with higher resolution than those onboard Viking 1 has lent credence to the view of the Face being a natural formation, a rocky hill or mesa with crevices on top simulating the features of a giant face staring upward from the Martian surface.

The “Face of Mars” is not the only formation on the Cydonia plain having created both interest and controversy. Some of them have been seen as further evidence for the existence of an ancient, intelligent civilization on Mars. There are numerous formations reminiscent of eroded pyramids, ruined castles, and other structures claimed to have an artificial origin. However, the evidence for the artificiality of these formations, along with the “Face of Mars”, is not nearly conclusive enough, and the general view is that they are natural products of geologic processes. Nevertheless, the structural anomalies on the Cydonia plain are well worth a thorough investigation because of both their fame and the contribution their study would give to our knowledge on Mars and various processes shaping its surface – whatever the outcome.

The exploration of Cydonia would also give information on the nature of the borderline between the rugged south and smooth north. The area is possibly an ancient coastline with several processes having affected its evolution either concurrently or consecutively – or both. Landing a manned mission on the Cydonia plain would – in addition to the obvious impact on the imagination of the public and media – enable extensive studies of the ancient shoreline and its alterations. This could also shed light on the climate change which caused the transformation of a temperate planet into a frozen celestial object, a kind of “Museum of Water”. Situated on the mid-latitudes (40°N) Cydonia would also be an ideal target for the studies on the effects of the variability in the obliquity of the rotational axis of Mars.

At the moment the inclination is very close to that of Earth – 25°11’ of Mars compared with 23°59’ of Earth – but it has been known a long time that there is a variability of at least 20 degrees over a period of approximately 100 000 years (Ward 1973). However, the variability seems to be chaotic, and during periods of tens of millions of years the inclination could have changed several tens of degrees (Touma et al. 1993). Because of the chaotic nature of the variability it is impossible to track it precisely for more than a few million years into the past, but with statistical methods it is possible to analyze the history of these variations. The value for the maximum of the obliquity is 82°, and the probability for the obliquity having reached 60° during the past 1 billion years is 63 %, and during the past 3 billion years as high as 89 % (Laskar et al. 2004).

This kind of variation has had a dramatic effect on the climate of Mars in the past, and most probably is still having: the variability of the inclination is continuous. While the inclination is small and the planet rotates in an upright position, the polar areas receive much less solar energy than the lower latitudes, and are thus much colder. When the inclination increases, the poles receiving more solar energy warm up, but the equatorial regions cool down.

This variability is the probable cause for the presence of the large reservoirs of near-surface ice in high latitudes of both northern and southern hemispheres of Mars. While the obliquity is high, there is an accumulation of ice, most probably even in the form of glaciers, to the equatorial regions, but during low obliquity, the sublimation of these reservoirs results in deposition of ice to the high latitudes and polar regions (Levrard et al. 2004; Forget et al. 2006).

With a thicker atmosphere in the past this has affected the state of water and consecutively the sea level of the Arctic Ocean, but also the migration of water from the polar areas to the mid- and low- latitudes (Haberle et al., 2004). This in turn could be inferred from the current depth and thickness of permafrost present also beneath the surface of Cydonia.

5. Noctic Labyrinthus

Noctis Labyrinthus just south of the equator of Mars is a place of major upheaval – or “downfall” to be precise. It is an area of large mesas, broad and flat-topped mountains and hills with steep clifflike slopes, called “chaotic terrain”. According to early theories this chaotic terrain formed when large amounts of subsurface ice suddenly melted with the water flowing off (Carr and Schaber 1977) or groundwater being released from aquifers to create large outflows (Carr 1979), and the terrain collapsing as a result.

Noctis Labyrinthus east of the Tharsis region is a large area of “chaotic terrain”. [Credit: Viking/NASA/JPL/USGS

 

However, there is still no final word on the process creating these features, but water has certainly played a key role in the evolution of the area as shown by the hydrated minerals found in the area (Thollot et al. 2010). Presumably the melting of ice was caused by volcanic activity: Noctis Labyrinthus is adjacent to the Tharsis highlands having many giant volcanoes. An examination of this vast and varied area would yield information on the similar features observed in a smaller scale, like Reull Vallis close to the Hadriaca Patera volcano and several others.In between the flat-topped mesas of Noctis Labyrinthus there are deep depressions formed by outflow of water and collapse of the ground.[Credit: Mars Express/ESA]

Landing a manned mission in Noctis Labyrinthus would offer an opportunity to study the origin and evolution of the chaotic terrain characteristic of the area. It would be a challenge to make a pin-point landing to avoid the hazards of the rough surface. However, in 1969, Apollo 12 landed right on target, less than 200 meters from the Surveyor 3 probe sent to the Moon 2,5 years earlier. Pin-point landings on a distant celestial body are not impossible.

The average depth of Noctis Labyrinthus is about 5 km (Bistachi et al. 2004), so the atmospheric pressure, albeit still very low, would still be above average. Whether the net effect of it would be positive or negative as to the manned mission, is uncertain. Some areas of exploration like meteorology would benefit from the local climate of the valleys – condensate clouds made of water-ice crystals form in this region rather regularly – but this is also an area of dust storm activity.

Early morning water clouds in and around the canyons of Noctis Labyrinthus.[Credit:  Viking/USGS/JPL/NASA]

Noctis Labyrinthus could have a definite benefit for a manned mission. There is a possibility for an existence of caves, carved either by the flash floods caused by the sudden melting of subsurface ice, or volcanic flows forming lava tunnels. If existent, they would offer a natural shelter against the ultraviolet radiation of the Sun and the bombardment of the cosmic rays. Otherwise they both would require either a heavily shielded landing craft or a base camp dug beneath the surface. Because of increased mass of the craft these alternatives would make a manned mission more challenging both technically and economically. Noctis Labyrinthus would be interesting also because of its proximity to two extensive surface features with a history still largely unknown: Tharsis and Valles Marineris. The former is evidently of volcanic origin – there are four giant volcanoes on top of Tharsis – and Valles Marineris was formed by rift faults in the crust of Mars, thus being similar to the East African Rift Valley (Hauber et al. 2010), which has later been expanded because of erosion and massive landslides: it is a sign of a kind of “failed” tectonism. It is still unknown whether they are related to each other, and if so, how; and whether either is caused by the other, or are they both caused by some process even more global than either of them.

6. Polar Expedition

Landing on the polar regions would offer an excellent opportunity to explore the enigmatic and simultaneously variable surface features on the high latitudes of Mars. There are theories on how the polar formations like polygons, “spiders”, “forests”, and “swiss cheese”, related to the sublimation of either water or CO2 ice or both, and also larger, but still continuously evolving features like dune fields are formed, but to organize geological field trips to the most interesting of these areas might answer the question of the origin of these formations.

Geysers of CO2 carrying dust from the subsurface create curious patterns in the polar areas. Credit: MRO/NASA/JPL-Caltech/University of Arizona
The cause of “Swiss cheese terrain” found only near the southern polar cap are believed to be the differences in the rate of the seasonal changes of the CO2 and water ices. Credit: NASA/JPL/University of Arizona

 

 

Polygons on the “patterned ground” are reminiscent of the phenomena in the Arctic regions of Earth originating from the changes in the subsurface ice. Credit: NASA/JPL/University of Arizona

 

The polar regions of Mars are under continuous change. With the seasons the carbon dioxide migrates through the tenuous atmosphere from one pole to the other giving rise to a regular variation in the appearance of the polar caps (Smith et al. 2009). While the southern cap completely disappears during the spring of the southern hemisphere, the residual water ice of the northern one holds through the somewhat colder spring and summer of the northern hemisphere.

The retreating ice is annually leaving behind strange formations the nature and especially the birth processes of which are still largely unknown. The future missions to Mars will – and most probably has to – “live off the land” to the largest possible extent, so landing on or near the polar regions would be a viable option. Water in the form a permafrost is found more or less everywhere on Mars, but on the polar regions, as the Phoenix lander in 2008 proved, it is only few centimeters below the surface thus making it easy to reach and utilize (Smith et al 2009).

Phoenix probe landed on water ice covered with only a thin layer of dust and sand. Credit: Kenneth Kramer, Marco Di Lorenzo, NASA/JPL/UA,Max Placnk Institute

 

However, landing on the polar regions might prove too hazardous because of potential dust storms, landslides, and the CO2 ice covering the ground in winter. To avoid any unnecessary and foreseeable risks it might be more practical to establish a base camp on a safer area, but still within easy reach of the places of interest. This would require reliable and fast enough mode of transportation for the astronauts to be able to explore the area within the time-limit set by the duration of both the stay on the surface of Mars and the changing seasons.

7. Acidalian Mud

A question even more intriguing than the past and present existence of water on Mars – but closely related to it – is the one about life on Mars. Despite promising, yet controversial findings in meteorites originated from Mars (Thomas-Keprta 2009), there are no definite proofs neither for the existence nor non-existence of life.

The surface conditions of present-day Mars are very hostile to life or any organic matter, but in the warmer and wetter past there might have been abodes for life to emerge. Whether the conditions have been favorable for long enough time for life to evolve is another matter of dispute, but if there has been life of any kind, based on the current knowlegde it must have been related with the existence of water. One of the potentially promising areas for finding signs of life is Acidalia Planitia. Along with several other areas on the northern lowlands like Utopia, Isidis, and Chryse Planitia, Acidalia is covered in many places with formations resembling very much the mud volcanoes found on Earth. The latest research implies that the number of these potential mud volcanoes is almost 20 000, perhaps even 40 000 (Oehler and Allen 2010).

[Image:  Possible mud volcanoes found on Mars could give clues to the ancient Martian life – if there was any. Credit: HiRISE/MRO/LPL (U. Arizona)/NASA]

The mud volcanoes are formed by pressurized subsurface gas or liquid erupting to the surface carrying with it material from depths of up the several kilometres. It is possible that there has been – or even today could be – reservoirs of liquid water beneath the thick layer of permafrost; they could have been favorable for bacterial life similar to the extremophiles on Earth. If this is the case, there might still be organic material to be found in the mud and gravel transported to the surface by the eruptions.

Albeit being relatively young, perhaps late Hesperian or early Amazonian, decuded from the fact that they overlap older formations (Tanaka et al. 2005), the mud volcanoes of Acidalia are still two to three billion years old. The strong radiation and surface chemistry would have destroyed any evidence of organic matter, but inside the flat domes with diameters of one kilometre and heights of some 200 metres on average (Oehler and Allen 2010), there might still be some evidence of life to be found. However, reaching it would require, as in the case of the ancient shoreline of the Arctic Ocean, an expedition equipped with drilling machinery.

8. Clays of Mawrth Vallis

One of the oldest valleys on Mars, Mawrth Vallis, could also be potential site for finding signs of ancient Martian life. Recently is has been observed to bear evidence for a prolonged existence of aquatic environment very early in the history of Mars, when the climate of the planet was more temperate, and potentially suitable for life (Poulet et al. 2005).

A stable and long-term presence of large quantities of liquid water is implied by the deposits of hydrated minerals the formation of which requires wet conditions. However, there are different kinds of hydrated minerals, namely phyllosilicates and hydrated sulphates, which have their origins in different kinds of processes. Phyllosilicates, for example clay, are formed by alteration of minerals of magmatic origin having been in contact with water for a considerable length of time. On the other hand, hydrated sulphates are deposits formed from salted water, and their formation requires acidic environment, but not extended periods of contact with water.

[Image: Mawrth Vallis has Noachian deposits of phyllosilicate minerals with a possibility to find evidence on Martian life. Credit: HiRISE/MRO/LPL (U. Arizona)/NASA]

The detection of phyllosilicates in Mawrth Vallis strongly implies that there has been water on the surface of Mars for extended periods of time in the earliest, the Noachian era, of its evolution, long before the global climate change making Mars a less habitable planet. On Earth the clay minerals are capable of preserving microscopic life, so a thorough examination of the phyllosilicates on Mars could give an answer to the question concerning ancient life on the red planet.

9. Olympus Mons

Another possible landing site for a manned mission with a great potential to capture the imagination of the general public, but not in anyway without scientific benefits would be Olympus Mons, the highest mountain in the Solar System. It could be a key to several questions concerning both the ancient and recent history of Mars.

[Image:  Olympus Mons, the highest mountain in the Solar System, has possibly been active until rather recently, only few million years ago. Credit: Viking/USGS/JPL/NASA]

Olympus Mons is the greatest of the Tharsis volcanoes not only by height, but by the volume of erupted lava and by the time span there has been eruptions. The formation of the mountain is very similar with those on the Hawaiian islands, but because of the lack of plate tectonics on Mars, the volcanic hot spot has been immobile, and the lava has accumulated into just one gigantic mountain.

Based on research made on the aureole surrounding the mountain the origins of Olympus Mons have been dated to the Hesperian era (Fuller and Head 2003), so it is at least 2 billion years old, but there are volcanic flows with an age of just tens of millions, perhaps only few million years (Neukum et al. 2004). In addition to being active until geologically very recently, the volcanic activity has been episodic.

Making detailed studies on the different lava layers on Olympus Mons would enable dating the different stages in the evolution of the mountain with a better accuracy than the current estimates based on crater counts, and trying to find the cause for the periodical behaviour – and possibly for the formation of the Tharsis region as a whole.

Olympus Mons is often shrouded with CO2 ice clouds making it an ideal site also for meteorological observations. The nature of the clouds – composition, density, temperature – could be measured readily with a possibility to take samples of the ice crystals making up the clouds. The size of the mountain is such, that it has a major effect on the air currents and wind patterns in the atmosphere of Mars, and consequently on the Martian weather (Wolkenberg 2008). To make direct observations on the spot of origin of these effects would help develop more detailed models for both global and local weather phenomena.

All this could be done with robotic probes, but Olympus Mons might offer an extra benefit for a future base camp. The slopes of the mountain could hide a number of caves formed by collapsed lava tunnels. Just like in the case of Noctic Labyrinthus these would offer a natural shelter against the harsh radiation environment on the surface of Mars. The great height of Olympus Mons would also keep a base camp well above all but the largest, global dust storms.

A mountain with a summit rising 25 kilometres higher than the surrounding landscape might appear as an extremely challenging site for any, especially manned, mission and the activities related with it. In reality the slopes of the mountain – apart from the steep cliffs especially on the eastern flank of the mountain – are very gentle, with a gradient of only few degrees. Together with the low gravity of Mars of some 40 % that of Earth this would result in an easy traversing on Olympus Mons, not so much going uphill or downhill, but only walking or driving around.

The obvious downside of Olympus Mons as a potential landing site for a manned mission is the very probable lack of subsurface ice to be exploited by the expedition. If there were any ice, it would be very deep in the ground and practically unattainable without very heavy machinery.

10. Selecting the Target

Making the selection between various options for the landing site of a manned mission to Mars aimed at exploring the surface anomalies will not be a simple task. The arguments to be taken into account include both the safety and practicality of the mission, and the possibility to make in-situ studies with scientific results increasing our knowledge on the anomalies specifically and on the evolution of Mars in general. However, trying to meet these criteria is an effort worth making.

There are many reasons why future manned missions to Mars must include among their primary objectives the exploration and examination of these surface anomalies: to explore their true nature, to solve their origin, to find out their importance in the geologic evolution of the planet, and – not the least important of the reasons – to feed the imagination of general public and keep up public interest in continued exploration of our planetary neighbor.

[Credit: Journal of  Cosmology]

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Search For Extraterrestrial Genome: A Project Overview

SETG will test the hypothesis that life on Mars, if it exists, shares a common ancestor with life on Earth. There is increasing evidence that viable microbes could have been transferred between the two planets, based in part on calculations of meteorite trajectories and magnetization studies supporting only mild heating of meteorite cores. Based on the shared-ancestry hypothesis, this instrument will look for DNA and RNA through in-situ analysis of Martian soil, ice, or brine samples. By applying recent advances in microfluidics, embedded systems, and biological automation, our team is developing an instrument that can isolate, amplify, detect, and classify any extant DNA or RNA-based organism.

On Earth, very simple but powerful methods to detect life by the DNA polymerase chain reaction (PCR) are now standardly used. Due to massive meteoritic exchange between Earth and Mars (as well as other planets), a reasonable case can be made for life on Mars or other planets to be related to life on Earth. The sensitive technologies used to study the extremes of life on Earth can be applied to the search for life on other planets. Team  is working to develop a PCR detector for in situ analysis on other planets, most immediately, Mars.

The SETG Instruments

Strategies for detecting life on other planets have sought to avoid the assumption it would share any particular features with life on Earth. The most general strategies — seeking informational polymers, structures of biogenic origin, or chemical or isotopic signatures of enzymatic processes — look for features that all life is expected to exhibit. This generality comes at a cost: the strategies are not particularly sensitive, and more importantly, there are abiological routes to these life signatures. However, if life on Earth is actually related to life on other planets, we can use a far more powerful and information-rich technique developed to detect the most extreme forms of life on Earth.

MARTIAN METEORITES NAKHLA AND SHERGOTTY

On March 19, 1999, David McKay announced at the Lunar and Planetary Science Conference in Houston, that an additional pair of Martian meteorites contained “true micro-fossils from Mars.” The fossils actually resembled Earth bacteria in the process of reproducing. These “micro-fossils were found in a 1.3 billion year old Martian meteorite which fell to Earth near Nakhla, Egypt, and nanofossils were found in a 165 million-year old Martian meteorite that fell near Shergotty, India.

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On October 31, 1996, British scientists and planetary geochemists, Colin Pillinger, Ian Wright, and Monica Grady, announced that they too had discovered evidence that life once existed and thrived on the red planet –Martian life that flourished as recently as 600,000 years ago.

The British team analyzed two different Martian meteorites, including the fist sized rock scrutinized by NASA scientists. Specifically, they discovered a variety of organic compounds including complex organic molecules produced by and associated with carbon-based life forms in a chunk of Mars (EETA 79001) that had been blasted out some 600,000 years ago. By analyzing the various atomic weights of these chemical substances, the British team also reported that the ratios discovered match those of the oldest fossils and bacteria found on Earth; e.g. archaebacteria. Moreover, these scientists discovered “microbially produced methane” similar to the methane produced by bacteria known to live in cow guts as well as other locals on Earth. That is, they discovered chemical residue reminiscent and suggestive of cow flatulence! Farting cows on Mars?

Thus there is evidence that Living creatures have populated Mars for much of its history, from 4 billion years until 600,000 years ago. Indeed, there is considerable evidence that life may still be present on Mars. In a presentation in London at the Royal Society, the British team reported that “geologically speaking, there appears to be a good chance that life might still exist in protected areas on our nearest planetary neighbor.”

IS THERE STILL LIFE ON MARS

Because of the low temperatures, and lack of sufficient atmospheric shielding, water on the surface of Mars will either freeze, or boil off and turn to vapor. And yet, incredible amounts of water is frozen in the permafrost.

On 2008 NASA’s Phoenix Mars Lander touched down north of the Martian arctic circle. and beamed back evidence of freeze-thaw cycles in what proved to be frozen water within a couple inches of the top of the soil. Soon snow was sensed falling from the Martian clouds, and its camera captured images of hoarfrost. It also detected perchlorate, an energy source used by some Earthly microbes.

Evaporating ice on Mars over a 4 day period On earth innumerable species live within the permafrost, and even miles beneath frozen ice. Some are active. Yet others are dormant and awaken from their icy slumber when the ice begins to thaw.

Similar conditions favorable to biology are also present on Mars.

Because of seasonal changes in the tilt of the planet’s axis and its elliptical orbit, which brings it periodically closer to the sun, Mars’s poles warm dramatically releasing water which flows across the surface. Likewise, when exposed to sunlight, Martian rocks and soil are sometimes heated above freezing and water leaks onto the surface.

VIKING SPACE CRAFT DISCOVERS LIFE ON MARS

Unfortunately, the rovers and the Phoenix were not designed to test for the presence of life. Nevertheless, evidence for life on Mars was discovered in 1976, though for reasons that are not at all clear, NASA issued conflicting reports about the findings. Part of the problem was due to the fact that the two Viking space craft were sent NOT to where life may exist, but to those regions of Mars the least likely to contain life. The exploration sites were chosen for safety and not science. In addition, the equipment and experiments conducted by the Viking landers were not designed or calibrated properly, and were not sufficiently sensitive to detect the presence of microbes which might be living in permafrost or frozen tundra.

Yet, even with these limitations, biological activity associated with microbial activity including reproduction, was in fact detected. Specifically, the “Labeled Release” (LR) experiment took a sample of Martian soil and added a nutrient that contained radioactive carbon. The purpose was to detect the presence of radioactivity in the gasses released that would indicate biological activity. A control experiment treated a second sample that had been sterilized. In every experiment conducted, positive results were obtained from the unsterilized sample, and negative results were obtained for the sterilized sample. Thus,the LR experiment proved there was life on Mars.

However, a second series of experiments, employing a gas chromotagraph and mass spectometer was conducted to test for organic material associated with living organisms. Yet this experiment was so poorly designed and so insensitive that it would have been unable to find evidence of life on Earth under similar conditions. The GC/MS experiment required that a gram of soil had to contain over 100 million organisms before signs of life could be detected. When the GC/MS experiment was tested against Antarctic soil which was brimming with bacteria, it failed to find evidence of life.

Thus, whereas the LR experiment demonstrated the presence of life on Mars, not surprisingly, the GC/MS provided negative results. NASA administrators, however, overruled the scientists who designed the experiments, ignored the positive findings and issued a statement falsely claiming that no evidence of life was found he in fact evidence of life was present.

The business end of the current SETG instrument contains 2 cm x 2 cm microfluidic chip module containing tiny nanoliter wells where the real-time polymerase chain reactions occur. Tiny tubes feed in chemicals and blue light illuminates fluorescent dyes that help identify and analyze DNA molecules.

Increasing evidence, such as the low temperature transfer of  ALH84001, and theoretical calculations suggest that objects capable of carrying life have been transferred between solar system bodies with significant frequency. In addition, extremophiles have been discovered in Earth environments with high radiation and frozen conditions which, while not as extreme as those on Mars and other planets, demonstrate the incredible adaptability of microbes and suggest that habitable zones are much broader than previously thought. Together these facts raise the possibility that life could have been transferred between Earth and Mars perhaps early in the history of the solar system, and could survive on Mars to the present day. The SETG team is developing a very low power and lightweight instrument to test for life on other bodies, most immediately Mars, using the most sensitive known detector for Earthly life.

BioInformatics

The PCR strategy for life detection emerged from the exploration of the diversity of life, which revealed about 500 “universal genes” that are carried in the DNA of every known living thing on Earth. The gene that has changed the least over the past 3-4 billion years is the 16S (or the related eukaryotic 18S) ribosomal RNA gene. Ribosomal RNAs are the main structural and catalytic components of the ribosome, a molecular machine that translates RNA into proteins. It is the slow rate of change of the 16S gene that makes it the best detector of life. Within the ~1500 nucleotides of the 16S gene, there are multiple 15 to 20 nucleotide segments that are exactly the same in all known organisms. These regions of the 16S gene are essential for its catalytic activity and have remained unchanged over billions of years.

Schematic representation of COLD-PCR

Image via Wikipedia

The DNA sequence between the universal 16S gene primers contains so much information that organisms detected only by their 16S gene sequences are routinely classified based only on that information. This DNA sequence carries information about the organism from which the ribosomal RNA gene is derived, and can allow a new organism to be fit into the tree of life.Thus the detected product is a unique biosignature. Currently, hundreds of research groups use 16S ribosomal RNA PCR primers to prospect for new archaeal and bacterial species from a wide range of environments. Most of the life that is detected by PCR cannot be grown in the lab, suggesting either very slow growth rates or very particular growth conditions not met in the lab. Thus the previous culture-based exploration of microbial diversity missed 99% of the living world. Such surveys of extreme environments have expanded habitable zones from below 0 °C to over 110 °C, from acidic hot springs to highly radioactive reactor pools, to deep in the crust of the Earth, and has allowed particular 16S gene sequences to be assigned to particular metabolic strategies.

The distinct environments of the Earth and Mars at present might not allow an organism adapted to one planet to grow on the other. But meteoritic exchange in the solar system was 100 to 1000x more intense during the heavy bombardment stage 4 billion years ago. There are signs of numerous fluid flows a possible ancient ocean, and sedimentary formations on Mars that suggest a warmer and wetter Mars 3 to 4 billion years ago, an environment more similar to Archean Earth.

Fossil evidence suggests that by the Archean period, microbial evolution on Earth had already proceeded to the point of modern microbial morphologies, and biosignatures suggest that enzymatic carbon metabolism with isotopic fractionation had evolved by then. Because all known organisms have one or more copies of the 16S ribosomal gene, all organisms are thought have inherited their ribosomal RNA gene from a common ancestor. This common ancestor has been hypothesized to be an archaeal-like hyperthermophile 3 to 4 billion years ago whose metabolism exploited oxidation/reduction gradients. Thus at the time of maximal meteoritic exchange 3.5-4 billion years ago, microbial life on Earth may have already possessed a shared core of 500 genes, including the 16S ribosomal RNA gene. The last common ancestor with life on Mars may have also shared this core of genes. Thus at the point of high meteoritic exchange, there may have been microbial life on Earth detectable by 16S gene PCR and an environment on Mars more similar to Earth than today.

Real Time PCR and Detection

Polymerase Chain Reaction (PCR) that is a detection strategy used to amplify the number of copies of a specific region of DNA in order to produce enough DNA to be further analyzed. A DNA sequence is the precise order of appearance of four different deoxyribonucleotides: adenine, thymidine, cytosine and guanine, abbreviated A, T, C and G, respectively. The technology of PCR involves adding stable 15-20 nucleotide long DNA primers, a stable enzyme nucleotide triphosphate monomers, and a simple heat pump that thermally cycles 20-30 times in 2 hours. Upon heating to 95°C and then cooling to 55°C, these DNA primers pair with their complement on each DNA strand, even if there are only a few DNA molecules in a sample. After heating to 75°C, the DNA polymerase will polymerize the nucleotide monomer components also in the tube to duplicate the DNA strands. There will now be four strands, where originally there were only two. If one repeats the thermal cycle with all the same components in the same tube, now there will be eight strands; repeat again – now 16, etc. Thirty cycles will produce one billion copies of the original sequences.

The principle behind the real-time PCR method is that as the amplification process progresses, there is an increase in the fluorescence from the dye binding to double-stranded DNA molecules. As the dye binds to DNA, it undergoes a conformational change and emits fluorescnece at a greater intensity, which we can then monitor.

PCR will even amplify complex mixtures of 16S ribosomal RNA genes from communities of organisms in environmental samples. Thus, PCR with DNA primers corresponding to the conserved elements can be used to amplify DNA from any species more than a billion fold, without need to isolate, culture, or grow the organism in any way. The PCR approach has added advantages of extreme sensitivity and robustness. PCR can detect a single DNA double helix in a crude sample. The biochemical processing of the sample can be as crude as a cheek swab from humans to agitation of dirt for soil microbes.

PCR technology is very mature, with thousands of thermal cycling machines installed in small labs all over the world, and field PCR thermal cyclers used, for example, in the military to detect biological warfare agents. They are as standard in the modern molecular biology laboratory as toasters are in kitchens. A typical small thermal cycler not optimized for space flight weighs 3 kg and uses 100W. Only tiny amounts of energy are actually needed to cyclically heat and cool the 10-100 microliters of fluid in a typical PCR reaction, and to detect the product of that amplification. Real-time PCR uses a fluorescent dye that intercalates with double-stranded DNA in order to allow for simultaneous detection and quantitation during the PCR reaction. The SETG team is engineering an instrument for real-time PCR that incorporates all the fluid handling components on a single microfluidic module.

Soils on Earth are considered to be a complex environment and a major reservoir of microbial genetic diversity. In the past two decades, progress in the development of methods to isolate nucleic acids from environmental sources and amplify them using Polymerase chain reaction (PCR) have shed light on a previously unknown diversity of organisms. However, since PCR is a highly-sensitive detection strategy, contaminants of metagenomic DNA can often interfere with PCR by inhibiting DNA and polymerase interactions.

A variety of different strategies have been investigated for the purification of metagenomic DNA from terrestrial environmental samples, such as sample pre-processing, agarose gel purification, electroelution, gel filtration, combinations thereof, as well as commercially available DNA extraction kits. Nucleic acid sample preparation on the lab bench is highly labor intensive and time consuming with multiple steps required to collect DNA or RNA from raw samples. More recently, microfluidic systems have been used to solve the sample preparation challenge by reducing analysis time, reagents consumed, and reducing cross contamination. The SETG team is developing a microfluidic sample preparation module for extracting and purifying a raw environmental sample that will serve as the front-end of the SETG instrument.

The definitive analysis of any PCR product is a DNA sequence determination. The current laboratory DNA sequencing technique, high-resolution electrophoresis, is not practical on Mars. Currently, there are a number of sequencing techniques available at the macroscale, which can be miniaturized to integrate into our SETG instrument. Additionally, some promising microfluidics-based sequencing technologies are now coming into the market, which we hope to collaborate with and/or draw insight from in order to develop a DNA sequencer that will meet our needs. For the flight instrument, all of the chemical and biochemical reagents will be need to be stored in a desiccated form. Though these reagents are known to be stable on Earth to cold and low level of radiation, their stability in vacuum and high solar radiation flux will need to be addressed during our development phase. In order to study how space radiation levels will affect the chemicals needed for a PCR reaction, the SETG team tested exposure of the reagents to proton, neutron, and heavy ion bombardment at levels on par to a typical mission to Mars. We are testing the survival of reagents on this mock interplanetary cruise, as well as Mars surface temperatures and radiation environments.

The primary purpose of Project RedGENES was to collect bacterial and archaeal genetic sequence data from the extremely acidic watershed of the Copahue Volcano and the Upper Rio Agrio in Argentina. Chemical similarities to Mars make the site astrobiologically interesting and an ideal setting to carry out a field test of the SETG instrument. The field campaign began with a reconnaissance of the Upper and Lower Rio Agrio, followed by the selection of six sites for in-depth study. The team collected water and soil samples from a range of locations within the highly acidic, low cell density study sites. The instrument prototype performed well in the field, with excellent hardware and software execution and power requirements were met with the use of a portable external battery. Geochemical analysis and bioinformatical analysis are being performed to characterize the bacterial and archaeal communities in these samples, and SETG hopes to return to the field site in the near future to collect new samples and perform additional instrument tests.

After all, it’s interesting to see such a project going on…Limitation?

[In next article, I’ll review the case for SETG and I’ll propose some strategies.]

[Credit: SETG Homepage]

SETG: Search for Extraterrestrial Genome on Mars

Many pathetic optimistic attempts have been made by scientific pioneers to detect at least ‘a single signature of life ‘ on other planets. With NASA funding, Carr and colleagues at MIT are developing a prototype device to decode alien DNA, a project known as the Search for Extraterrestrial Genomes (SETG). They hope to fly an instrument as part of a joint NASA-European Space Agency mission to Mars slated to launch in 2018. When hypothesizing about life that may exist elsewhere in the universe, the tendency is to visualize something far different from life here on earth. But here in our galactic neighborhood, a team of MIT researchers argues, life it just as likely related to us.

The premise of their reasoning is this: It’s estimated that Mars and Earth have swapped a billion tons of rock over the course of their lifetimes. And some of the stow away microbes aboard those rocks could be quite hardy, surviving the trip. DNA is pretty durable as well. On the surface of Mars it wouldn’t last too long, but shielded from UV radiation DNA could lie dormant on Mars for a million years or so. So MIT’s DNA decoder will be designed to dig. If there ever was life on Mars, or if there are organics buried there from other origins – be they Earth or elsewhere – the Search for Extraterrestrial Genomes (SETG) should be able to isolate, amplify,and identify nucleic acids right there on the Mars, no return trip necessary. The technology is still a couple of years away from field tests in Chile’s Atacama Desert or in Antarctica, two of Earth’s analogs for the arid, cold deserts of Mars. If it passes muster there, it could be hunting the building blocks of life on the Red Planet by the dawn of the next decade.

A widely disseminated consensus is that there is no life on Mars as its atmosphere is full of UV radiation and no organic DNA could survive in such a rather harsh environment. Yet sampling soil from under a rock on Mars demonstrated that UV light was not inducing the LR activity detected. “Strong oxidants were present that destroy life and organics”. Findings by the Viking Magnetic Properties Experiment showed that the surface material of Mars contains a large magnetic component, evidence against a highly oxidizing condition. Further, three Earth-based IR observations, by the ESA orbiter failed to detect the putative oxidant in any amount that could cause the LR results, and, most recently, data from the Rover Opportunity have shown Mars surface iron to be not completely oxidized (ferric) – but to occur mostly in the ferrous form which would not be expected in a highly oxidizing environment.

We already have compelling evidences that suggests that there should be life on Mars. Huge advances in the research of extremophiles on Earth have added very strong import to the current context. Recently, an expert in soil science from the Netherlands communicated to the congress of the European Geosciences Union that the discovery of the recent detection of phyllosilicate clays on Mars may indicate pedogenesis processes, or soil (as opposed to regolith) development, extended over the entire surface of Mars. This interpretation views most of Mars surface as active soil, colored red, as on Earth, by eons of wide spread microbial activity.

However, this project is full of endeavour to detect alien life. The suggested strategies would be:
1. This should be designed so that it can detect almost any complex organic compound and biomarkers of extinct life, if there was any and gone extinct due to various planetary calamities, like lipids and other complex proteins.
2. The detector should be capable of detecting other complex compound like bizarre compounds of silicon, boron etc or co-ordination compounds that may be significant to alien life forms.
3. The omnipresence of intense orderliness and of structures and of events utterly improbable on a basis of thermodynamic equilibrium. Extreme departures from an inorganic steady-state equilibrium of chemical potential. This orderliness and chemical disequilibrium would to a diminished but still recognizable extent be expected to penetrate into the planetary surface and its past history as fossils and as rocks of biological origin.
4. Search for Order in chemical structures and sequences of structure. A simple gas chromatograph or a combined gas chromatograph – mass spectrometer instrument would seek ordered molecular sequences as well as chemical identities.
5.Looking and listening for order: A simple microphone is already proposed for other (meteorological) purposes on future planetary probes; this could also listen for ordered sequences of sound the presence of which would be strongly indicative of life. At the present stage of technical development a visual search is probably too complex; it is nevertheless the most rapid and effective method of life recognition in terms of orderliness outside the bounds of random assembly.

Enhope we’ll find aliens in 2018.
[Ref:PopSci]

Reason to Believe Life on Mars

It was just another reason to believe that Mars may be the last colony intelligent species live in before migrating to Earth. More recently, NASA has confirmed water on Mars ,giving scientist another place to study whether the environment could have sustained life. Some scientist including me believe that Mars was the place where an intelligent civilization prospered once till Mars lost its electromagnetic poles because the nuclear reactor at core ran out of fuel. The deposits of salts confirmed by Mars Odessey Orbiter in recent years, appears to be disconnected making it most probable that they did not all come from one big global body of surface water. Many of the deposits lie in the basins with channels leading into them, which is the kind of feature consistent with water flowing in over a long time. More recently a meteor said to be came from Mars was lurking with bacteria giving rise to the panspermia hypothesis. Worth considering is that if a meteor that was facing too much radiation of space was bacteria rich, then why not Mars? Mars is still eden for life. Currently NASA confirmed water on moon and Mars. Media has its own role to reveal what is truth. I think NASA had found water on moon and Mars earlier, but they were part of classified and secret knowledge. At that time media was not so active that’s why they hadn’t disclosing it. If they can send human to moon in 1969 then why could not find water? Denial and falsification have always suppressed me. But it doesn’t matter because now they are disclosing truth. And now I could expect soon we’ll hear news, “Hey, we have found life on Mars. Now Nasa is planning for a Mars base and colony”. I’m still believing that there are rodents on mars, life on mars.

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