NASA: Water on Mars Lakes Existed Long After the Red Planet Dried Up

Scientists have long known that there was a time water existed in the lakes and streams on Mars. New data recently revealed that the timing is a bit off by roughly a billion years; some of the bodies of water in the planet were found to have formed much later than initially believed.

According to an official report from NASA, the data collected was from the NASA Mars Reconnaissance Orbiter. Evidence gathered in the planet's northern Arabia Terra region revealed that there were water sources that appeared about a billion years after the era of Mars when water is known to have existed. This suggests that a later era in the planet may have been suitable for life as well.

"We discovered valleys that carried water into lake basins," said Sharon Wilson of the Smithsonian Institution, Washington, and the University of Virginia, Charlottesville. "Several lake basins filled and overflowed, indicating there was a considerable amount of water on the landscape during this time."

It's not a measly stream of liquid, but a vast body of water that Wilson compared to Lake Tahoe, which contains about 45 cubic miles. She said, "This particular Martian lake was fed by an inlet valley on its southern edge and overflowed along its northern margin, carrying water downstream into a very large, water-filled basin we nicknamed 'Heart Lake.'"

By studying the valleys and surrounding debris from craters, the researchers concluded that these water bodies likely appeared between two to three billion years ago. This time period seems like forever ago, but it is way after water is thought to have already frozen on the planet's surface.

The valley properties also revealed much about the source of water, which the researchers believe are runoff from melted snow rather than rain. Similar valleys exist throughout Mars.

"A key goal for Mars exploration is to understand when and where liquid water was present in sufficient volume to alter the Martian surface and perhaps provide habitable environments," Rich Zurek, Mars Reconnaissance Orbiter Project Scientist of NASA's Jet Propulsion Laboratory, Pasadena, California, explained. "This paper presents evidence for episodes of water modifying the surface on early Mars for possibly several hundred million years later than previously thought, with some implication that the water was emplaced by snow, not rain."

The report was published in the Journal of Geophysical Research, Planets. Authors include Wilson, Alan Howard of the University of Virginia; Jeffrey Moore of the NASA Ames Research Center, Moffett Field, California; and John Grant of the Smithsonian.