|Last: 12. The Milky Way and Other Galaxies||Next: 14. The Big Bang|
|Ch. 11||CLUSTERS AND SUPERCLUSTERS (p. 246)|
|Ch. 11-14||Galaxies are gravitationally bound into clusters and superclusters|
|Ch. 11-15||Clusters of galaxies may appear densely or sparsely populated and regular or irregular in shape|
|Ch. 11-16||Galaxies in a cluster can collide and combine|
|Ch. 11-17||Galactic halos may account for some of the dark matter in the universe|
|Ch. 11||SUPERCLUSTERS IN MOTION (p. 252)|
|Ch. 11-18||The redshifts of superclusters indicate that the universe is expanding|
This is a compact group of spiral and elliptical galaxies. While groups of galaxies are common, only a small fraction are as compact as the one shown here.
The Hercules cluster is unusually rich in spiral galaxies. A number of interacting galaxies are visible in this image.
This animation shows a trip through the Local Supercluster, a region about 80 Mpc in diameter containing a number of galaxy clusters.
This image shows regions of high galaxy density. The box is about 400 Mpc across.
These fan-shaped surveys reveal the foam-like texture of the galaxy distribution. The Milky Way is at the point where the two fans meet; each fan extends to a distance of about 800 Mpc.
This is a computer simulation of the formation of dark halos by gravitational collapse. In this animation, color shows density. Note how several small halos merge to form a single larger one; such mergers probably built up the Milky Way's halo more than 10 billion years ago.
Computer simulation showing how the collision of two disk galaxies could create the famous `Antennae Galaxies'.
Computer simulation showing the interactions and eventual merger of galaxies in a compact group over roughly 4 billion years.
Compuer simulation of a merger of the Milky Way and the Andromeda Galaxy.
Further computer simulations of galactic collisions.
This movie shows the motion of stars near the center of the Milky Way over a period of eight years. From the observed motions of these stars we can infer the presence of a massive black hole in the center of our galaxy!
Homework 13: Hubble's Law, due 11/27.
Last modified: November 20, 2001