Curiosity rover confirms Mars once had long-lived lakes

Less than two weeks after confirming the existence of water on Mars, NASA announced on Thursday that the Curiosity rover proved that the Red Planet could have stored H2O in lakes and streams over extended periods of time  billions of years ago.

Members of the US space agency’s Mars Science Laboratory team, including researchers from the California Institute of Technology (Caltech), analyzed data obtained by Curiosity and found that water once helped deposit sediment into the rover’s original landing site, Gale Crater.

The sediment deposited as layers, ultimately forming the foundation of Mount Sharp, the large mountain found in the middle of Gale Crater today, the researchers explained in a statement. A paper detailing the team’s findings was published in Friday’s edition of the journal Science.

“Observations from the rover suggest that a series of long-lived streams and lakes existed at some point between about 3.8 to 3.3 billion years ago, delivering sediment that slowly built up the lower layers of Mount Sharp,” explained MSL project scientist and study co-author Ashwin Vasavada. “However, this series of long-lived lakes is not predicted by existing models of the ancient climate of Mars, which struggle to get temperatures above freezing.”

Mudstone provides clues about Mount Sharp’s formation

Billions of years ago, Mars appeared to have a more massive atmosphere, contributing to an active hydrosphere capable of storing water in these basins, the study authors explained. The new findings build upon previous research that also suggested that the Red Planet was likely home to ancient bodies of water, NASA said.

“What we thought we knew about water on Mars is constantly being put to the test,” Michael Meyer, lead scientist with NASA’s Mars Exploration Program, said. “It’s clear that the Mars of billions of years ago more closely resembled Earth than it does today. Our challenge is to figure out how this more clement Mars was even possible, and what happened to that wetter Mars.”

After landing in Gale Crater and beginning its journey, Curiosity stopped at several points along the way to image different targets, collect soil samples, and, on occasion, drill into rocks in order to obtain samples. These samples were placed in the rover’s onboard laboratories, then examined using various instruments to help the MSL team discover how this area of Mars evolved.

Prior to Curiosity’s arrival, scientists proposed different hypotheses to explain how Gale Crater became filled with sediment layers. Some scientists suggested that the that sediment accumulated from wind-blown dust and sand, while others suggested the layers had been deposited in ancient lakes. The new findings indicate that at least the bottom layers of Mount Sharp occurred via the so-called “wet” method over a period of no more than 500 million years.

“During the traverse of Gale, we have noticed patterns in the geology where we saw evidence of ancient fast-moving streams with coarser gravel, as well as places where streams appear to have emptied out into bodies of standing water,” said Vasavada. “The prediction was that we should start seeing water-deposited, fine-grained rocks closer to Mount Sharp. Now that we’ve arrived, we’re seeing finely laminated mudstones in abundance that look like lake deposits.”


Image credit: NASA