spacetoday.net: Early Mars had large ocean

Posted: Fri, Mar 6, 2015, 7:23 AM ET (1223 GMT)
Mars ocean illustration (NASA/GSFC)

Scientists reported Thursday that Mars, early in its history, likely had an ocean larger than the Arctic Ocean on Earth today. In a paper published in the journal Science, planetary scientists estimated the amount of water Mars once had by measuring the ratio of water in the Martian atmosphere with HDO, where one hydrogen atom is replaced by deuterium, a heavier isotope. Measuring the current ratio of HDO to water and comparing it to that measured in water trapped in an ancient Martian meteorite, scientists were able to determine how much water escaped from Mars since early in its history. That led them to conclude that early Mars had enough water to support an ocean with a volume of 20 million cubic kilometers, larger than the Earth's Arctic Ocean.