It was believed that Martian lakes and rivers dried up about 3 billion years ago. But a new analysis shows that Mars harbored water much more recently.

Although Mars today is a dry and barren place, we have known for some time that in bygone times liquid water flowed liberally over the Martian surface. This is generally thought to have been the case until about 3 billion years ago. However, in a new study, researchers come to a surprising conclusion. Because Mars appears to have harbored water much more recently. And that means there may have been longer life as well.

Water on Mars

There are numerous signs on Mars that indicate that large amounts of water once flowed over the planet. Think of wavy land stripes visible from space, branches and riverbeds. Researchers are very interested in this. Because where there was water, there may once have been life. For example, the Martian lakes and rivers may well have been potentially habitable environments for microbial life. However, as the planet’s atmosphere thinned out over time, all that water evaporated. And what’s left is the frozen desert world that NASA’s… Mars Reconnaissance Orbiter (MRO) today.

Study

In a new study, researchers looked at collected data from the MRO over 15 years. And the team makes a surprising discovery. As mentioned, Martian lakes and rivers were thought to dry up about 3 billion years ago. But researchers have now found new evidence that suggests that didn’t happen until much later. For example, researchers found relatively young salt deposits left behind when ice-cold meltwater flowed through the landscape.

Photo of NASA’s Mars Reconnaissance Orbiter from Bosporos Planum; an area on Mars. The white dots are salt deposits in a dry channel. The largest impact crater on site is almost 1.5 kilometers wide. Image: NASA/JPL-Caltech/MSSS

After analysis, these salt minerals appear to have been deposited about 2 billion years ago. And so it seems that liquid water could still be found on the red planet about 2 to 2.5 billion years ago.

Chloride salts
The researchers discovered the salt deposits – chloride salts to be precise – in clay-rich highlands located in the southern hemisphere of Mars. Here we find pockmarked terrain, marked by impact craters. These craters were key to dating the salts found: the fewer craters an area has, the younger it is. By counting the number of craters in an area of ​​its surface, scientists can estimate its age.

The discovery of these remarkably young salt minerals is important for several reasons. Although we know from certain drawings in the Martian landscape that water once flowed over Mars, the salt deposits provide the first mineral evidence confirming the presence of water.

martian life

In addition, the discovery raises new questions about possible microbial life on Mars. If water existed on Mars for much longer, there would also be more time in which life could have developed. And that means it may have lasted much longer than expected.

The research once again shows the inestimable value of the meanwhile aging Mars Reconnaissance Orbiter see, which arrived at the red planet way back in 2006. “Part of the value of MRO is that this instrument has made our view of the planet more and more detailed over time,” said study researcher Leslie Tamppari. “And the more we map the planet with our instruments, the better we will understand its history.”