Published: Apr 28, 2010 6:13 PM EDT

WASHINGTON  - Scientists have found lots of ice in an unexpected place in our solar system: an asteroid between Mars and Jupiter.

The discovery of significant asteroid ice has several consequences. It could help explain how Earth first got its water. It makes asteroids more attractive to explore. And it muddies the definition between comets and asteroids.

The distant asteroid has an extensive but thin frost coating that is likely replenished by frozen water deep inside the rock. The discovery was announced in two studies being published in Thursday's issue of the journal Nature.