NASA's Valentine date with a comet

February 14, 2011 8:22:29 AM PST
After eyeing a comet for the past four years, a NASA spacecraft will finally make its move.

The Stardust craft is expected to fly within 125 miles of comet Tempel 1 on Valentine's night, snapping pictures of the surface.

Tempel 1 was visited by another NASA probe in 2005 when Deep Impact fired a copper bullet into the comet, excavating a crater.

If successful, it'll be the first time scientists will have before-and-after images of Tempel 1.

Scientists are interested in comets because they're leftover building blocks of the solar system.