CL 0542-4100: Two clusters of galaxies about 5.7 billion light years from Earth.
Caption: These galaxy clusters show that younger, more distant galaxy clusters contained far more active galactic nuclei (AGN) than older, nearby ones. It was found that the clusters at 58% of the Universe’s current age contained about 20 times more AGN than those at 82% of Universe’s age. The galaxies in the earlier Universe contained much more gas that allowed for more star formation and black hole growth. In the Chandra X-ray images, red, green, and blue represent low, medium, and high-energy X-rays.
Scale: Each panel is approx. 10.8 arcmin across
Chandra X-ray Observatory ACIS Image