Astronomers have discovered an orbital region just beyond Jupiter that appears to act as a kind of gateway for some objects entering the inner solar system from the Kuiper Belt. The discovery may offer a solution to a puzzle that has long confused astronomers: How does a certain class of objects from the Kuiper Belt become comets?
Many comets take a straightforward path into the solar system’s inner regions. They come from the Kuiper Belt or the Oort Cloud – regions beyond Neptune containing millions of icy leftovers from the solar system’s beginning. Gravitational nudges send them plunging inward until whey swing around the Sun and out again.
The puzzle comes from space rocks called Centaurs. First discovered in 1977, these objects from the Kuiper Belt have been gravitationally jostled into unstable orbits between Jupiter and Neptune. Close encounters with one of the giant planets can send a Centaur back ...
