This artist's concept depicts a recently discovered ring encircling the dwarf planet Quaoar, which is in the Kuiper Belt, far beyond the orbit of Pluto. Computer models say the ring shouldn't be there, so planetary scientists are trying to explain its existence. Quaoar's moon, Weywot, is depicted at the left, with the Sun, roughly four billion miles away, at right. [ESA]
Find out more in our radio program entitled Inconvenient Rings.