The main reason why explore Mars is to determine whether life ever existed there. But we are looking in the wrong places
When searching something, the first step is to look at the most probable. This does not always work. Things sometimes appear in unexpected places. But most of the time the milk is in the fridge, the phone is on the table, and keys are next to the door. Why search for life on Mars should be different?.
The main reason to explore Mars is to determine whether life ever emerged on the planet. We have tried for centuries, from telescopes and more recently with satellites, landers and rovers.La we searched directly (Viking mission ) or indirectly (for each mission to Mars). No luck so far. Some think that life has never been there. Others think it was there in the past but has been ahora.Muchos think why bother, but that's another story. I think we're looking in the wrong places. Here's why.
The surface of Mars is very cold and dry. The cosmic radiation and solar reach the surface without obstacles in the thin atmosphere and the soil contains strong oxidants that destroy organic compounds. It was not always so.
Early in its history Mars was warmer and humid enough for the development of rivers, lakes and possibly oceans. The atmosphere was thicker and the protective magnetic field was active. Mars might be uninhabitable today, but life would have been possible in the past. This is the reason why future missions will focus on the study of ancient sediments in the hope of finding fossil evidence of life.
Is there or was there life on Mars? is the big question will be resolved over time as more exploratory probes sent to the appropriate places in planeta.Crédito.Nasa.
But first we have to find a promising place, and that means to reconstruct the history of Mars. We have to find out if there was water flowing, the timing and extent of water, what type of minerals formed and whether the geochemical conditions were consistent with life. Once you identify promising sites, we have to find out if there is any physical or chemical process that could have destroyed the fossil evidence, and finally find such evidence.
This is not easy, and that is why the search is becoming more ambitious, complex and costly. The Mars Science Laboratory (MSL) will be launched this year to study the habitability and environmental history of a region of Mars that contains sediments that formed billions of years. The MSL is the most advanced robot ever sent to another planet. Around 2018, a joint mission conducted by NASA and the European Space Agency will send two rovers to the surface to pave the way for the mission Mars Sample Return after 2020. Be the first mission to collect and return samples from another planet. Its scientific value is enormous, but the process could swallow the NASA Planetary budget for the decade.
Is this the best strategy? I think not. Back to our planet for a second. On Earth, life is almost everywhere, but some places seem to be out of bounds. At first glance, the Atacama Desert in Chile and the dry valleys of Antarctica appear lifeless, and until recently thought they were.
Atacama is the driest desert on Earth, with only an occasional shower in 10 years or so. The Antarctic dry valleys are the coldest deserts on Earth. Most water in the soil freezes, and little snowfall sublimates before it can derretirse.En liquid water both places, the key ingredient for life, is extremely rare. These deserts are the closest analogue we have on the Martian surface and allow us to study what happens to life when the environment becomes drier and colder.
What happens is that life takes refuge in the niches where liquid water can still be formed, if only for a short period of time in when.they.are occurs in two substrates, salts and ice. The salts absorb water vapor from the atmosphere to form liquid solutions at low relative humidities, a phenomenon called deliquescence . When the ice is in contact with sediment particles, melt and form thin films of liquid water is stable even at temperatures below zero.
In other words, the salt and ice extend the window of the physical conditions under which liquid water is stable, and provide habitable niches, even though the general environment becomes uninhabitable. In the Atacama Desert, where most of the water in the atmosphere, life inside salt rocks, while in the dry valleys of Antarctica is at the interface between ice and snow sediments. It
the salt and ice are also excellent substrates for the preservation of life. Ancient salt deposits and ice on Earth containing organic compounds, complex biomolecules and even whole cells have been preserved for millions of years. Therefore, the last niches where life may be withdrawn when an environment becomes drier and cooler are also the niche where the remnants of life are better preserved - a stroke of luck that plays to our favor.
More good news: there are salty environments Marte.Grandes ice and salt deposits are widespread in the southern hemisphere, the north polar cap is thick sequences of sediments and ice sheets and ice near the surface at latitudes above 60 ° in both hemispheres. If there was ever life on Mars, these are the niches where it could have retired when the planet made the transition from warm to cold and wet and dry. These are also the places where the fossils of life would be better preserved. And these should be the first places to seek it.
This could be done with small missions and low cost. A small vehicle or the lander could provide unequivocal evidence of life, if equipped with the technology to detect complex biomolecules are synthesized only by living organisms. The technology is available. A result would be a positive turning point in history. A negative result would be strong evidence against the presence of life and biomolecules anywhere in the world. There is a small reward for a relatively small investment. Author
note Alfonso F. Davila the SETI Institute in Mountain View, California.
source of information:
http://www.newscientist.com/article/mg20928005.900-looking-for-life-on-mars-try-the-salty-bits.html
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