By Ron Cowen
Part one of a two-part series on recent findings in X-ray astronomy and on its future
When it comes to recording the hottest, most violent, and most bizarre interactions in the universe, X rays win hands down over visible light. During their normal aging process, stars and galaxies give off lots of visible light. But whenever galaxies collide, stars explode, or chunks of matter plunge into massive black holes, they emit a torrent of X rays, which are 100 to 1,000 times more energetic than the light you can see.