SIGH OF PAST
Martian ocean that was
Artist's impression of a Martian ocean shoreline seen from the air based on satellite images.
NAMED after the Roman God of war, Mars is still a mystery in the human quest of the Heavens. Even though lately the talk of water on moon has resurfaced, it has always been Mars, which captivated people's imagination as far as extra-terrestrial liquid and life-forms are concerned. Before getting into details it is sensible to point out that the current atmospheric condition of Mars is not hospitable enough to sustain liquid water on its surface. But numerous researches suggest that Mars was once a wet planet with plenty of liquid water flowing down the surface, much like Earth's oceans. And according to a recent study conducted by the University of Colorado (CU) at Boulder, it is likely that a vast ocean covered one-third of the surface of Mars some 3.5 billion years ago. Published in the latest edition of the journal Nature Geoscience, planetary geologists from the United States, after studying a ring of ancient Martian delta deposits and valley networks from the databases of NASA and European Space Agency, strongly imply that up to a third of Mars was under about 30 million cubic miles of liquid water. The study further maintains that the ancient red planet probably had an Earth-like global hydrological cycle, including precipitation, runoff, cloud formation, ice and groundwater accumulation which strongly supports the commonly held idea that the planet may have once harboured a rich array of extra-terrestrial life forms. The river deltas on Mars are of high interest to planetary scientists, mostly because deltas on Earth rapidly bury organic carbon and other biomarkers of life and scientists believe same is the situation in the Martian deltas. According to CU-Boulder researcher and lead author of the study, Gaetano Di Achille, "On Earth, deltas and lakes are excellent collectors and preservers of sign of past life. If life ever arose on Mars, deltas may be the key to unlocking Mars". It is important to mention here that the CU-Boulder study is the first to combine the analysis of water-related features including scores of delta deposits and thousands of river valleys to test the existence of an ocean sustained by a global hydrosphere on early Mars. Using images taken by different satellites, the researchers looked at the remains of 52 Martian river deltas, each fed by numerous river valleys. And it was found that 29 out of these 52 deltas were connected either to the ancient Mars Ocean or to the groundwater table of the ocean and to several large adjacent lakes. Di Achille and his team-mate, Dr. Brian Hynek, used a geographic information system (GIS) to map the Martian terrain and concluded that the ocean might have covered about 36% of the planet and contained about 30 million cubic miles or 124 million cubic kilometers of water. The amount of water in the ancient ocean would have formed an equivalent of 1800 foot or 550 meter deep layer of water spread over the one third of the 4.6 billion year old planet. According to Dr. Hynek, the volume of the ancient Martian ocean would have been about 10 times less than the current volume of Earth's oceans, since Mars is slightly more than half the size of Earth. The researchers also found that the large, ancient lakes upslope from the ancient ocean probably formed inside impact craters and would have been filled by the transport of groundwater between the lakes and the ancient sea. Another separate study headed by Dr. Hynek, detected roughly 40,000 river valleys on Mars, which is about 4 times the number of river valleys that were previously been identified by scientists. All in all, both scientists agreed that, these collective findings only strengthen the existing theories on the extent and formation time of an ancient ocean on Mars and imply that the surface conditions during the time probably allowed the presence of a global and active hydrosphere integrating valley networks. With eyes on the future, Di Achille stated, "One of the main questions we would like to answer is where all of the water on Mars went". Scientists are hoping that future Mars missions like NASA's $485 million Mars Atmosphere and Volatile Evolution mission or MAVEN which is scheduled for launch in 2013, will finally provide some insights into this mysterious 4th planet from the Sun. .....................................................................
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