On Feb. 15th an asteroid about half the size of a football field will fly past Earth closer than many man-made satellites. Since regular sky surveys began in the 1990s, astronomers have never seen an object so big come so close to our planet
ASTEROID FLYBY - SpaceWeather.com: At 2:25 p.m. EST (19:25 UTC) on Friday, Feb. 15th, asteroid 2012 DA14 will fly past Earth only 17,200 miles above our planet's surface. This will put it well inside the orbit of geosynchronous satellites, closer than any asteroid of the same size has come since regular sky surveys began in the 1990s.
Researchers speculate that Earth's gravity might even cause seismic activity on the 50m-wide space rock...click SpaceWeather.com link for more