NASA Scientists Claim They've Confirmed that Early Mars Had an Ocean
Astrobiologists have long been convinced that Mars was once host to water, and the theory that the northern part of the Red Planet was once covered by a bonafide ocean has been increasing in popularity in recent years. Now, NASA researchers have found evidence that they believe to be all but definitive that Mars was once the home of a sea as large as the Arctic Ocean.
"The existence of a northern ocean has been debated for decades, but this is the first time we have such a strong collection of data from around the globe," said co-author of the study Michael Mumma, principal investigator at NASA's Goddard Center for Astrobiology. "Our results tell us there had to be a northern ocean."
In order to come to this conclusion, the researchers examined the ratio of "heavy" to "light" water in the Martian atmosphere. "Heavy" water refers to water in which there is a larger than normal amount of a hydrogen isotope called deuterium. Heavy water has all the same physical properties as normal or "light" water, except that it is heavier in mass. Earth has a very specific signature ratio: three deuterium atoms per every 10,000 molecules of water.
According to their findings, Mars has approximately eight times as much heavy water as Earth, which indicates that a far greater amount of light water must have been lost. Co-author Geronimo Villanueva, a planetary scientist at NASA, said that the discovered amount of deuterium "provide[s] a solid estimate of how much water Mars once had by determining how much water was lost to space." Although the ocean is thought to have covered the northern sector of the planet, their calculations show that Mars once had enough water to form a global ocean of 450 feet. While other scientists have predicted a Martian ocean, this is the highest estimate of the amount of water so far.
Although some in the scientific community are skeptical that this is true "confirmation" rather than just further evidence for a hypothesis, if the findings are accurate, it would have major implications for our search for extraterrestrial life. According to Paul Mahaffy, chief of the atmospheric experiments laboratory at the Goddard Space Flight Center, "The more water was present - and especially if it was a large body of water that lasted for a longer period of time - the better the chances are for life to emerge and to be sustained."