The massive Perseus Cluster stretches out over 15 million light-years

At first glance, this looks like just another star field. But almost every source of light in this image is actually one of the 190 galaxies making up the massive Perseus Cluster, one of the nearest such clusters to Earth. » 7/12/11 2:33pm 7/12/11 2:33pm

Galactic hyperclusters are too big for the universe

Gravity forces galaxies that are relatively close together to form clusters, which in turn form superclusters between vast stretches of cosmic void. But now there's an even bigger level of organization...and we have no idea how to explain it. » 6/22/11 4:30pm 6/22/11 4:30pm