<P> On December 9, 2013, NASA reported that the planet Mars had a large freshwater lake (which could have been a hospitable environment for microbial life) based on evidence from the Curiosity rover studying Aeolis Palus near Mount Sharp in Gale Crater . </P> <P> Comets contain large proportions of water ice, but are generally thought to be completely frozen due to their small size and large distance from the Sun . However, studies on dust collected from comet Wild - 2 show evidence for liquid water inside the comet at some point in the past . It is yet unclear what source of heat may have caused melting of some of the comet's water ice . </P> <P> Nevertheless, on 10 December 2014, scientists reported that the composition of water vapor from comet Churyumov--Gerasimenko, as determined by the Rosetta spacecraft, is substantially different from that found on Earth . That is, the ratio of deuterium to hydrogen in the water from the comet was determined to be three times that found for terrestrial water . This makes it very unlikely that water found on Earth came from comets such as comet Churyumov--Gerasimenko according to the scientists . </P> <P> The asteroid 24 Themis was the first found to have water, including liquid pressurised by non-atmospheric means, dissolved into mineral through ionising radiation . Water has also been found to flow on the large asteroid 4 Vesta heated through periodic impacts . </P>

For the earth to have liquid water on its surface