NEW STUDY: SOME ASTEROIDS MAY BE LAYERED LIKE ONIONS A new study of several meteorites collected on Earth and thought to have come from the same large asteroid reveal the structure of the parent space rock to have been something like an onion, with layer upon layer of differing structure. The asteroid, long ago destroyed in a collision, was once hot enough to have a molten core and cooled from the outside inward, the research shows, confirming a long-held expectation that had eluded supporting research. Asteroids are leftovers of planet formation. While some rocks got together to build planets about...