New Mission
Two and a half years ago, a space mission known as Deep Impact provided the first close-up look below the surface of a comet. Now, it's trying to look more than skin-deep into planets in other star systems.
Deep Impact made headlines when it fired a big "cannonball" into a comet in 2005. The impact blasted out a cloud of debris, giving scientists a glimpse below the comet's surface.
The craft's instruments are still in good shape, so a few months ago, NASA gave it two new missions. One is to fly past a second comet, one year from today. And on the way, it'll turn its telescopic cameras and instruments toward other star systems.
Deep Impact will target systems where astronomers have already discovered giant planets.
The spacecraft will watch for transits -- where a planet passes directly in front of its star, blocking some of the star's light. Precise measurements of how a star fades and brightens as the planet passes across it may reveal whether the planet has rings or moons. Continued observations may reveal whether the system has other planets -- including Earth-like planets in Earth-like orbits.
Astronomers have already discovered a handful of planets with this technique, both from ground-based telescopes and from spacecraft. A new mission, called Kepler, may find hundreds more. It's scheduled for launch in early 2009. You can find out more about Kepler on the web, at kepler.nasa.gov.
We'll talk about an old transit tomorrow.
Script by Damond Benningfield, Copyright 2007
For more about the Kepler Mission, visit NASA's website at http://kepler.nasa.gov.
For more skywatching tips, astronomy news, and much more, read StarDate magazine.
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