The asteroid 2005 YU55, which is about 1,300 feet (400 meters) across, will make its closest approach to Earth at 6:28 p.m. EST (2328 GMT) today. At that point, the space rock will be traveling at about 29,000 mph and be about 201,700 miles (324,600 kilometers) from Earth — closer than the moon, which orbits 238,864 miles (384,499 km) from us on average.
The flyby will mark the closest such a big space rock has come to Earth since 1976. But there's no need to scurry down to the basement bunker to await an asteroid impact, researchers say.
that's really close!