A team of amateur astronomers has discovered a previously unknown asteroid in orbit that brings it near the Earth, highlighting the contributions regular folks can make to planetary defense, scientists announced Wednesday (Oct. 12). The skywatchers spotted the asteroid, which is known as 2011 SF108, in September using a telescope in the Canary Islands. While 2011 SF108's orbit appears to bring it no closer to Earth than about 18 million miles (30 million kilometers), it still qualifies as a near-Earth object — the class of space rocks that could pose a danger to our planet. The team took advantage of...