On October 19, 2014, Comet C/2013 A1 Siding Spring will sweep closer to Mars than our moon is to Earth. Dust shed by the comet could endanger spacecraft orbiting Mars.
This is the smallest object by far found to have rings and only the fifth body in the solar system - after planets Jupiter, Saturn, Uranus and Neptune - to have rings.
Every night, the Automated Planet Finder checks the weather, decides which stars to observe, and moves the telescope from star to star, looking for distant planets.