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Asteroid Collision

April 20, 2006

Asteroids are space rocks that orbit the sun — mainly in the region between Mars and Jupiter called the asteroid belt. One listener wants to know what it would be like to fly through the asteroid belt.


Navigating the asteroid belt. I’m Bob Hirshon and this is Science Update.

Listener Cyril Emery of Silver Spring, Maryland, asks why spacecraft sent beyond Mars don’t crash when passing through the asteroid belt.

Well, astronomer Sean Raymond of the University of Colorado says the asteroid belt isn’t nearly as dense as sci-fi movies would have you believe. In fact, the total mass of all the asteroids is just 4 percent that of the moon, and they’re spread out over billions of miles.

SEAN RAYMOND (University of Colorado):
So the chance of encountering one—if you’re not trying to—is very small. And typically if you’re going to go to an asteroid you go out of your way to go and have a close flyby and take some pictures.

…as several space missions have done.

If you have a science question, call us at 1-800-why-isit. If we use it on the air, you’ll win a Science Update mug. I’m Bob Hirshon, for AAAS, the science society.