Why is a NASA spacecraft crashing into an asteroid
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Why isa NASA spacecraft crashing into an asteroid?
In thefirst-of-its kind, save-the-world experiment, NASA is about to clobber a small,harmless asteroid millions of miles away. A spacecraft named Dart will zero inon the asteroid Monday, intent on slamming it head-on at 14,000 mph (22,500kph). The impact should be just enough to nudge the asteroid into a slightlytighter orbit around its companion space rock — demonstrating that if a killerasteroid ever heads our way, we’d stand a fighting chance of diverting it.
“This isstuff of science-fiction books and really corny episodes of “StarTrek” fromwhen I was a kid, and now it’s real,” NASA program scientist Tom Statler said Thursday.Cameras andtelescopes will watch the crash, but it will take days or even weeks to findout if it actually changed the orbit.
The asteroidwith the bull’s-eye on it is Dimorphos, about 7 million miles (9.6 millionkilometers) from Earth. It is actually the puny sidekick of a 2,500-foot(780-meter) asteroid named Didymos, Greek for twin. Discovered in 1996, Didymosis spinning so fast that scientists believe it flung off material that eventuallyformed a moonlet. Dimorphos — roughly 525 feet (160 meters) across — orbits itsparent body at a distance of less than a mile (1.2 kilometers).
“Thisreally is about asteroid deflection, not disruption,” said Nancy Chabot, a planetaryscientist and mission team leader at Johns Hopkins University’s Applied PhysicsLaboratory, which is managing the effort. “This isn’t going to blow up theasteroid. It isn’t going to put it into lots of pieces.” Rather, the impactwill dig out a crater tens of yards (meters) in size and hurl some 2 millionpounds (1 million kilograms) of rocks and dirt into space. NASA insists there’sa zero chance either asteroid will threaten Earth — now or in the future.That’s why the pair was picked.