Mars had climate suitable for life 4 billion years ago

​London: Now cold and dry Red Planet had a warm and wet climate about four billion years ago, said researchers after analysing fossilised riverbeds discovered on an ancient region of the Martian surface.

The team from the University College London identified over 17,000 km of former river channels on a northern plain called Arabia Terra, providing further evidence of water once flowing on Mars.

"We've now found evidence of extensive river systems in the area which supports the idea that Mars was warm and wet, providing a more favourable environment for life than a cold, dry planet," explained led author Joel Davis.

Since the 1970s, scientists have identified valleys and channels on Mars which they think were carved out and eroded by rain and surface runoff, just like on the Earth.

Similar structures had not been seen on Arabia Terra until the team analysed high resolution imagery from NASA's Mars Reconnaissance Orbiter (MRO) spacecraft.

The new study examined images covering an area roughly the size of Brazil at a much higher resolution. The team revealed the existence of many systems of fossilised riverbeds which are visible as inverted channels spread across the Arabia Terra plain.

The inverted channels are similar to those found elsewhere on Mars and the Earth.