The Mars Phoenix crew has just announced they've discovered ice on Mars. There will be more tests soon, and ones that should be more direct in their analysis. Today's discovery is based on the visualized disappearance of some white material from the surface over the past few days. From the Mars Phoenix web site:

June 19, 2008 -- Dice-size crumbs of bright material have vanished from inside a trench where they were photographed by NASA's Phoenix Mars Lander four days ago, convincing scientists that the material was frozen water that vaporized after digging exposed it.

"It must be ice," said Phoenix Principal Investigator Peter Smith of the University of Arizona, Tucson. "These little clumps completely disappearing over the course of a few days, that is perfect evidence that it's ice. There had been some question whether the bright material was salt. Salt can't do that."

Very cool stuff, and it will be even more interesting to see what's next:

Also early today, digging in a different trench, the Robotic Arm connected with a hard surface that has scientists excited about the prospect of next uncovering an icy layer.

And how/where did the news come to us? Via Twitter!

You can follow http://www.twitter.com/marsphoenix for regular updates if you wish. The specific ice updates from today on Twitter are here and here.