Human Spaceflight, Space Exploration UPDATE: NASA sets new target launch date for space shuttle Discovery
Science I read somewhere that mercury is being used to make liquid-mirror telescopes. What are the advantages of collecting light this way?
Exotic Objects Do black holes and their accretion disks always spin in the same direction? Does a supermassive black hole always spin in the same direction as its host galaxy?
Solar System Saturn’s rings are said to contain chunks of icy debris as big as cars. Why are none of the larger particles visible in the Cassini photos?
Science When a star in a binary system goes supernova, what happens to its companion? Is it destroyed?
