Scientists believe Mars may have been habitable for millions of years longer than previously thought.
They say the planet could have been home to life before it finally dried out. The surface of the red planet was once covered in oceans, lakes and rivers.
It would have resembled Earth during the earliest days of the solar system, reports The Times.
The theory means life could have evolved in Martian waters, but not long enough to have developed into a complex organism.
Scientists believe any life on Mars would have been wiped out when the liquid water vanished from the planet’s surface, around three billion years ago.
There are however competing ideas about what happened to the water. Studies believe it could have evaporated into space as the planet’s atmosphere thinned.
Or become bound with the planet’s crust before it sank to create an icy layer of permafrost.
It is previously thought Mars lost its water during the Hesperian period, around 3.7 billion to 2.9 billion years ago. Scientists now believe water could have been on Mars until the late Hesperian period.
Researchers at Imperial College London have now “found signs that water was abundant in Mars’s Gale crater, a 92-mile diameter basin just south of the equator, long after the planet was thought to have become dry and inhospitable”.
The Curiosity rover research team also found deformed layers in desert sandstone that they say could have been made only by water.
Dr Steven Banham, lead author of the study, published in the journal Geology, and a teaching fellow at Imperial’s Department of Earth Science and Engineering, said: “The sandstone revealed that water was probably abundant more recently, and for longer than previously thought, but by which process did the water leave these clues?
“This water might have been pressurised liquid, forced into and deforming the sediment; frozen, with the repeat freezing and thawing process causing the deformation; or briny, and subject to large temperature swings. What’s clear is that behind each of these potential ways to deform this sandstone, water is the common link.”
