A bizarre object that sometimes gets as close to the sun as Saturn, and other times retreats as far out as Uranus, has been discovered to have a transforming disk of dust around it that changes shape and can even mimic rings.
Minor planet 2060 Chiron is what's known as a Centaur, which are captured cometary objects that travel around the sun on looping orbits between Jupiter and Neptune. Chiron is just 218 kilometers (135 miles) across and occasionally has outbursts like a comet. To date, however, no spacecraft has ever visited a Centaur.
