Talk about a close shave. On Feb. 15th an asteroid about half
the size of a football field will fly past Earth only 17,200
miles above our planet’s surface. There’s no danger of a
collision, but the space rock, designated 2012 DA14, has NASA’s
attention. “This is a record-setting close approach,” says Don
Yeomans of NASA’s Near Earth Object Program at JPL. “Since
regular sky surveys began in the 1990s, we’ve never seen an
object this big get so close to Earth.” Earth’s neighborhood is
littered with asteroids of all shapes and sizes, ranging from
fragments smaller than beach balls to mountainous rocks many
kilometers wide. Many of these objects hail from the asteroid
belt, while others may be corpses of long-dead, burnt out
comets. NASA’s Near-Earth Object Program helps find and keep
track of them, especially the ones that come close to our
planet. 2012 DA14 is a fairly typical near-Earth asteroid. It
measures some 50 meters wide, neither very large nor very small,
and is probably made of stone, as opposed to