Foster Comets

There's a huge population of comets orbiting at a vast distance from our Sun - what's known as the Oort cloud. But theories vary about why they're there, and where they come from.

Astronomers suspect our solar system formed in a cluster with other newly forming stars, all of which would have thrown out most of its native comets. So they caught some of our comets, and we caught some of theirs. Thus, many of the comets in the Oort cloud may be fosterlings from other systems.

Audio Embed: CBC Radio's Quirks & Quarks 6/12/10, Guest Host: Alison Motluk.