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Active galaxies pour out lots of energy, due to their central supermassive black holes gobbling down matter. Galaxies tend not to be loners, but instead exist in smaller groups and larger clusters. Our Milky Way is part of the Local Group, and will one day collide with the Andromeda galaxy. Clusters of galaxies also clump together to form superclusters, the largest structures in the Universe. In total, there are hundreds of billions of galaxies in the Universe.
First Air Date : Jan 15, 2015
Last Air date : Dec 24, 2015
Episode : 46 Episode
Season : 1 Season
Runtime: 12:14 minutes
Studio: YouTube
Country:
Cast: Phil Plait
Crew: Phil Plait (Writer)