Mars was not always the dry planet we know today. Evidence suggests that four million years ago, liquid water used to flow across the Martian surface and form pools and lakes! Jezero crater is one such long-dried-out lake found by the U.S. National Aeronautics and Space Administration (NASA). Many other stream and lake beds have also been discovered.
Scientists say that if Mars had been able to hold liquid water in the past, its atmosphere and climate too, would have been vastly different back then. Maybe, once upon a time, it was like Venus, or the Earth! After all, all the three planets are made up of similar materials. So in their early stages, their surface conditions may have been similar too! But over the years, these planets became quite different – the Earth and Venus still have most of their thick protective atmosphere, whereas Mars was able to retain only a thin layer.
Water on Mars today exists majorly as polar ice caps, 3.7 kilometres thick in the south, and 1.5 to 2 kilometres thick in the north. Water is also present in the Martian atmosphere as ice and vapour. But in comparison, the Earth’s atmosphere is richer in water content by nearly a hundred times! As a result, Mars’ precipitation is also considerably lesser than the Earth’s – even cold seasons produce only a thin film of frost, less than a millimetre thick!
Picture Credit : Google
