NASA finds evidence confirming water flowed on Mars longer than previously thought

NASA’s Mars Reconnaissance Orbiter (MRO) on Wednesday found that water flowed on the Red Planet longer than previously thought. According to a blog post, the MRO determined that water left salt minerals on the surface of Mars as recently as two billion years ago. The US space agency stated that the detection of salt signatures is the first mineral evidence confirming the presence of liquid water in the inhospitable world.

It was previously believed that Mars’ water evaporated about 3 billion years ago. However, as per the blog, two scientists studying MRO data over the last 15 years found evidence that reduces the timeline significantly. Their research revealed signs of liquid water on the Red Planet as recently as 2 billion to 2.5 billion years ago, meaning water flowed there about a billion years longer than previously estimated. 

“What is amazing is that after more than a decade of providing high-resolution image, stereo, and infrared data, MRO has driven new discoveries about the nature and timing of these river-connected ancient salt ponds,” said Ehlmann, CRISM’s deputy principal investigator in a statement.

The findings of the research centre on the chloride salt deposits left behind as icy meltwater flowing across the landscape evaporated. The scientists said that the salt deposits provide the first mineral evidence confirming the presence of liquid water. Now, the discovery raises new questions about how long microbial life could have survived on Mars if it ever formed at all. 

'The more of the planet we map, the better we can understand'

The research was conducted by Ellen Leask as part of her doctoral work at Caltech. As per the blog, Leask used data from the MRO instrument called the Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) to map the chloride salts across the clay-rich highlands of Mars’ southern hemisphere terrain pockmarked by impact craters. She explained that these craters were one key to dating the salts: The fewer craters a terrain has, the younger it is. By counting the number of craters on an area of the surface, researchers can estimate its age.

NASA said that MRO has two cameras that were used to create digital elevation maps. The scientists found that many salts were in depressions once home to shallow ponds on gently sloping volcanic plains. Moreover, they also found winding, dry channels nearby former streams that once fed surface runoff (from the occasional melting of ice or permafrost) into these ponds.

“Part of the value of MRO is that our view of the planet keeps getting more detailed over time,” said Leslie Tamppari, the mission’s deputy project scientist at JPL. “The more of the planet we map with our instruments, the better we can understand its history.”

(Image: NASA/Pixabay)