... HCG 87: A Small Group of Galaxies . 6.09.1999 . ... Small, compact groups, like Hickson Compact Group 87 (HCG 87) shown above, are interesting partly because they slowly self-destruct. The Universe Evolves . ... It's only Planet Earth, of course ... as seen on the Water Vapor Channel. ... Eclipse Over The Mountain . ... The two stars at the center of this nebula are very different. One is a white dwarf star with a mass similar to our Sun but with a radius as small as our Earth. ...