class=”c7″ src=”http://referentiel.nouvelobs.com/wsfile/1351386696274.jpg” Curiosity was first discovered on the surface of Mars for evidence of what was once a freshwater (NASA / SIPA) lake.
With Curiosity, we now have new evidence of the existence of fresh water on Mars in the past. It is an indisputable progress. It is customary, in fact, consider that for life as we know it today is possible somewhere, three conditions must be met:
1. The presence of liquid water
2. The presence of carbon, hydrogen, sulfur, oxygen, nitrogen and phosphorus in proportions sufficient
3. The existence of a power source (in most cases it is photosynthesis or digestion of the materials derived from photosynthesis).
However, all these elements have been identified in the explored by Curiosity where this lake is formed area. This discovery has therefore further strengthen a little more assuming a favorable environment for life on Mars.
We have gradually to a significant number of certainties about it.
A similar lake to those observed on Earth
According to data provided by Curiosity, the explored area also appears to be a little acid neutral place. Specifically, this lake was likely to resemble those that can be observed on Earth, notably with mud and rocks at the bottom edges.
It is interesting to note, moreover, about those rocks, those that have been observed to show very little altered chemically. This means that they were relatively well preserved.
This finding is interesting in more ways than one. It allows in particular to know a little more about the type of climate that existed at this location in March.
good condition of these rocks suggests that this lake was formed in an arid environment and probably cold. An environment may be close, in fact, that of dry vallies found in Antarctica today, namely an average temperature of – 30 degrees, with ice. The presence of liquid water could be explained by periods of melting ice.
This is a scenario of a once ice on Mars where I worked for several years, and this new discovery seems to go in this direction.
If these revelations are important, but many issues remain unresolved.
It would be interesting, for example, know how long it has existed lake. The team believes that Curiosity took at least a few hundred years to file the rest of the lake sediments after erosion, but it is not impossible that the original thicker deposits requiring millions of years to deposit were present.
The best way to prove that there was life on Mars would be, of course, to find a fossil. But before such a revolution intervene, there is much more research to be conducted. Mini laboratory SAM aboard Curiosity seems to have revealed the presence of carbon-rich molecules can be organic in clays. This is a first step.
The main issue that we need to work now involves the formation of clays. Are they the result of a long alteration of liquid water, over thousands of years, or have they been transported to this place with water in a timely manner?
analysis geologists of the mission looks for the first hypothesis. If this is confirmed, it is, in my view, a great surprise, which confirms the interest of the site explored by Curiosity suggesting that the conditions of life on Mars has made this place for the long periods.
Interview by Sébastien Billard