Scientists have long believed that Mars was once covered with a river and a lake system. NASA’s Perseverance rover explored the ancient river delta, which carries proof that a massive river flowed into the Jezero crater, filling it up and creating a large delta billions of years ago. However, the source of this water has not been found yet.

Advertisment

“We picked Jezero Crater as a landing site because orbital imagery showed a delta – clear evidence that a large lake once filled the crater. A lake is a potentially habitable environment, and delta rocks are a great environment for entombing signs of ancient life as fossils in the geologic record,” Perseverance’s project scientist, Ken Farley of Caltech, said.

Also Read: A hole reappeared in Antarctica after 40 years. We now know what caused it

Mars is seen as a cold and dry planet. But researchers believe it was once warm and wet, and according to a new study, the water came from incessant rains. The red planet seemingly witnessed regular rain at one point in its history, which fuelled the vast networks of river valleys and lakes. However, 

Advertisment

The study has been published in the Journal of Geophysical Research: Planets. 

Also Read: 500-billion-year spin solves a cosmic puzzle: Panta Kykloutai, the universe is rotating

The team of researchers ran computer simulations which showed that the water bodies on Mars weren't formed by the melted ice caps, but from precipitation. They state that Earth's neighbour wasn't always icy, but warm and wet.

Advertisment

Was Mars ever like Earth?

The team was trying to understand if Mars ever had a climate like Earth's. They made a digital version of part of Mars and analysed different scenarios, some with rain and snow and others with melting polar ice. Using software, they created a scenario in which the water continued to flow for thousands of years. What happened then?

This is where the breakthrough happened, as water formation differed in the two scenarios. Adding rain and snow to the climate showed the formation of valleys and streams at varying elevation points. But when it was only from melted ice, the valleys formed only in regions near these ice caps.

They also looked at the Martian surface as captured by NASA spacecraft from orbit. The patterns on land were similar to what one would expect when rain and snow fell on the ground. NASA says snowfall still happens on Mars, although it has never been caught on camera. It occurs at the poles when it gets extremely cold and at night when clouds cover the planet.