Washington, Oct 1
The Phoenix Mars lander has found snow falling from clouds above Mars, NASA has said.
The snow evaporated before it reached the ground, Phoenix's instruments showed.
"Nothing like this view has ever been seen on Mars," researcher Jim Whiteway of York University in Toronto said. "We'll be looking for signs that the snow may even reach the ground."
Scientists also said they had found calcium carbonate - the main component of chalk - and possibly clay, both of which form only in the presence of liquid water.
Phoenix earlier confirmed there was ice on the surface of Mars. Determining whether liquid water has ever been present on Mars is key to learning whether life could have ever survived on the rocky planet.