The Physics To Go website will be unavailable Friday evening through Saturday afternoon as electrical work occurs in the American Center of Physics server room. Down time will begin at 6PM Eastern Time on Friday. Service is expected to resume by 6PM on Saturday, July 30.

Quasars and Active Galaxies Feature Summary

Worth a Look
Quasars and Active Galaxies
Explore galaxies further by learning about the strange ones:

- Quasars, or quasi-stellar objects, are not stars as the name suggests. Learn about these distant sources of bright light here.
- Active galaxies are thought to be powered by black holes at their centers. Find out more at Introductory Astronomy: Active Galaxies.
- Colliding galaxies offer insight into our Milky Way Galaxy's future. See this APOD on the crashing Antennae Galaxies, and check out this simulation of the Milky Way and Andromeda galaxies colliding in the cosmologically near future.
December 16, 2009 - January 1, 2010