The wreckage of a few ancient planets formed the asteroid belt

A new study finds 85 percent of the asteroid belt came from five or six planetoids.

It's exciting to watch Japan's Hayabusa 2 craft close in on its chosen asteroid and start surveying it from up close, but we can still learn things about them from down here. A new study has determined that 85 percent of our solar system's asteroid belt between Mars and Jupiter is made up of the remnants of five or six ancient small planets.

The study appeared today in the journal Nature Astronomy, and according to its lead author, University of Florida theoretical astronomer Stanley Dermott, the remaining 15 percent could end up being from the same handful of very old planets. The origin of the asteroid belt could tell us more about Earth, but more pressingly, those hunks of rock and mineral occasionally peel off and hurtle toward our own planet.

"These large bodies whiz by the Earth, so of course we're very concerned about how many of these there are and what types of material are in them," Dermott said in a press release. "If ever one of these comes towards the earth, and we want to deflect it, we need to know what its nature is."