NEW YORK :A 54-pound (24.5-kg) Martian meteorite that is the largest known piece of Mars found on Earth has sold for $5.3 million at Sotheby's, setting a new auction record for a meteorite. The auction on Wednesday for the rock known as NWA 16788 sparked a 15-minute bidding war between online and phone bidders. "This is an amazing Martian meteorite that broke off of the Martian surface," said Cassandra Hatton, Sotheby's vice-chairman and global head of science and natural history, ahead of the