Puzzling objects found far beyond Neptune hint at second Kuiper belt

There just doesn’t seem to be enough of the Solar System. Beyond Neptune’s orbit lie thousands of small icy objects in the Kuiper belt, with Pluto its most famous resident. But after 50 astronomical units (AU)—50 times the distance between Earth and the Sun—the belt ends suddenly and the number of objects drops to zero. Meanwhile, in other solar systems, similar belts stretch outward across hundreds of AU. It’s disquieting, says Wesley Fraser, an astronomer at the National Research Council Canada. “One odd thing about the known Solar System is just how bloody small we are.” A new discovery is challenging that picture. While using ground-based telescopes to hunt for fresh targets for NASA’s New Horizons spacecraft, now past Pluto on a course out of the Solar System, Fraser and his colleagues have made a tantalizing, though preliminary, discovery: about a dozen objects that lie beyond 60 AU—nearly as far from Pluto as Pluto is from the Sun. The finding, if real, could suggest that the Kuiper belt either extends much farther than once thought or—given the seeming 10-AU gap between these bodies and the known Kuiper belt—that a “second” belt exists. The discovery, being prepared for publication and not yet peer reviewed, is supported by measurements from New Horizons itself, which at 57 AU continues to streak beyond the edge of the known Kuiper belt. Many of its instruments are in hibernation, but a dust counter has run continuo...
Source: Science of Aging Knowledge Environment - Category: Geriatrics Source Type: research