July 2, 2009

Phoenix Lander Team: It Snows at Night on Mars

Written by Nancy Atkinson

It snows on Mars. This occurs, at least in the northern arctic region where the Phoenix lander set up camp in 2008. Science teams from Phoenix were able to observe water-ice clouds in the Martian atmosphere and precipitation that fell to the ground at night and sublimate into water in the morning.

James Whiteway and his colleagues say that clouds and precipitation on Mars play a role in the exchange of water between the ground and the atmosphere and when conditions are right, snow falls regularly on Mars.

“Before Phoenix we did not know whether precipitation occurs on Mars,” Whiteway said. “We knew that the polar ice cap advances as far south as the Phoenix site in winter, but we did not know how the water vapor
moved from the atmosphere to ice on the ground. Now we know that it does snow, and that this is part of the hydrological cycle on Mars.”

Phoenix landed at the north arctic region on Mars (68.22°N, 234.25°E) on May 25th, 2008. On Mars, this was just before the summer solstice. Phoenix operated for 5 months, and was able to observe conditions as the seasons changed from summer to winter, giving science teams an unprecedented look at the planet's changing weather patterns, including frost and precipitation.

Full article here:

http://www.universetoday.com/2009/07/02/phoenix-lander-team-it-rains-at-night-on-mars/