High-powered telescopes can now peek at the origins of distant stars, but there’s still little we know about our own cosmic backyard. Take, for example, the outer solar system: the dark, comet-infested void beyond the planets. Writing for Space.com, Charles Q. Choi runs through some of the open questions surrounding the outer solar system.
One of Choi’s most intriguing unknowns is an area known as the Oort Cloud, a scattering of trillions of comets spinning in the far reaches of the solar system. It’s so far away from the sun that no human has ever actually see it, scientists have only inferred its existence. Some have hypothesized that the Oort Cloud was part of a “protoplanetary disk” that surrounded the sun some 4.6 billion years ago. Understanding the mysteries the cloud contains could give insight into the formation of our humble earth.