Mars was capable of supporting life for much longer than previously believed, say scientists who have discovered "halos" of silica-rich bedrock on the red planet.
But as of now, a new study has provided a dramatic evidence of transient liquid water -- a key element in the search for life outside our planet -- and its role in the daily interaction between surface salts and the Martian atmosphere. This has profound astrobiological implications since life, as we know it, depends on water.
In a new study published in Nature Communications, we simulated the atmospheric conditions on Mars to discover how these features could have come about without a big flow of water. For example, scientists have made assumptions about the water budget necessary to form the so-called “recurring slope lineae” — dark streaks at the surface, which appear annually (687 days) during peak temperatures and which dissolve in colder months at the Martian surface. But the water needed to create these features would be too high to come from the Martian weather each year.
About 3.8 billion years ago, when the temperature of the Red Planet was warmer liquid water flowed widely across the planet, shaping its surface as observed in riverbeds, deltas, teardrop-shaped islands, etc. The present frigid and parched landscape appears to be unfavourable for microbial life, except perhaps, in the subsurface of the dark streaks on slopes documented in the equatorial regions that gain and lose heat quickly, says Geographical studies on Mars
Until recently, the predominant hypothesis for the creation of these slope features was the phenomenon of ‘dry mass movement’ wherein dust avalanches and rockfalls are set off by local disturbances, perhaps quakes or meteor impacts. Alternatively, the lines on the slope could have been created by the flow of wet debris when ice melts. The research team, led by Dr. Anshuman Bhardwaj, a glaciologist by training, argues that the existing models fail when studying analogous terrain on Earth.
“With the available remote sensing data and climate simulations, we are very confident of the mechanisms which we have proposed. The reason why we have high confidence is that the results are not based only on the visual observations and measurements, but are also backed by very significant geo-statistical test results at global scale, for the first time”, comments Dr. Bhardwaj. “Furthermore, the fact that the analogous slope streak features which we find on the Earth are all related to wet flows is a very strong suggestive of a similar mechanism on Mars”, he adds.
The goal of Curiosity rover mission has been to find out if Mars was ever habitable, and it has been very successful in showing that Gale crater once held a lake with water that we would even have been able to drink, but we still do not know how long this habitable environment endured.