An overview of the Chandra mission and goals, Chandra's namesake, top 10 facts.
Classroom activities, printable materials, interactive games & more.
Overview of X-ray Astronomy and X-ray sources: black holes to galaxy clusters.
All Chandra images released to the public listed by date & by category
Current Chandra press releases, status reports, interviews & biographies.
A collection of multimedia, illustrations & animations, a glossary, FAQ & more.
A collection of illustrations, animations and video.
Chandra discoveries in an audio/video format.
Q&A: Dark Matter

Q:
George Gamow, in his book "The Creation of the universe," explained why the galaxies rotate as a solid body as actually being a "dipping elliptical trajectory" of the stars. So why are we looking for the missing matter when the "falling" of stars through galactic gas is more reasonable?

A:
I think Gamow was referring to the inner regions of galaxy. The outer regions don't rotate as a solid body, which has a constant angular velocity of rotation. Rather they have a constant linear velocity of rotation. The angular velocity declines inversely as the radius.

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