* Astronomy

Mystery cosmic objects light up in X-ray then go dim in an hour

In less time than it takes you to get ready for work, some X-ray emitting space objects become hundreds of times brighter than usual, then dim back down. But what those objects are, astronomers haven't yet figured out.
In 2003 and 2007, scientists detected two superfast, super-bright X-ray flares near a galaxy called NGC 4697. No one had found anything like them before or since - until astronomer Jimmy Irwin at the University of Alabama in Tuscaloosa announced today that his team has caught two more such flares.
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