Amateur astronomers have for the first time spotted a space rock—asteroid 2011 SF108—that it could pose an impact threat to Earth. The discovery was made last month at a from the ESA's Optical Ground Station at Teide on Tenerife in the Canary Islands. Even though the asteroid's orbit will bring it no closer than 18 million miles away, it is still classified as a near-Earth object and a possible danger to the planet. More from Space.com.