Astronomers have found the first evidence of the remains of a comet-like object scattered around a burned-out star. They used NASA's Hubble Space Telescope to detect the debris, which has polluted the atmosphere of a compact star known as a white dwarf. The icy object, which has been ripped apart, is similar to Halley's Comet in chemical composition, but it is 100,000 times more massive and has a much higher amount of water. It is also rich in the elements essential for life, including nitrogen, carbon, oxygen, and sulfur. These findings are evidence for a belt of comet-like bodies similar to our solar system's Kuiper Belt orbiting the white dwarf. This is the first evidence of comet-like material polluting a white dwarf's atmosphere. The results also suggest the presence of unseen, surviving planets around the burned-out star.
Peering from the shadows, the Saturn-facing hemisphere of tantalizing inner moon Enceladus poses in this Cassini spacecraft image. North is up in the dramatic scene captured last November as Cassini's camera was pointed in a nearly sunward direction about 130,000 kilometers from the moon's bright crescent. In fact, the distant world reflects over 90 percent of the sunlight it receives, giving its surface about the same reflectivity as fresh snow. A mere 500 kilometers in diameter, Enceladus is a surprisingly active moon. Data collected during Cassini's flybys and years of images have revealed the presence of remarkable south polar geysers and a possible global ocean of liquid water beneath an icy crust.
