Four "potentially hazardous" space rocks, which are between 100 and 580 feet across, will all make their closest approaches to Earth within less than 12 hours of one another on Thursday (Oct. 24). Two of them were only discovered earlier this month.

Four huge asteroids — and a fifth that's much smaller — are passing Earth on Thursday in their closest approaches to the planet ever recorded.

Four asteroids will make their closest approaches to Earth on Thursday (Oct 24) one after the other within a span of 12 hours. Two of these asteroids were discovered just this month, one of them only about a week back.