A space rock zips by earth Sunday night. Astronomers know it doesn't pose a threat, in part thanks to a new automated warning program called Scout.
'When a telescope first finds a moving object, all you know is it's just a dot, moving on the sky,' says Chodas. 'You have no information about how far away it is. 'The more telescopes you get pointed at an object, the more data you get, and the more you're sure you are how big it is and which way it's headed. But sometimes you don't have a lot of time to make those observations.