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:
Regarding the Dark Matter Mystery. Did the equation for the mass of the galaxy include planetary zones for the stars? Just looking at our own solar system, a large proportion of the mass seems to be in the planetary zone and made up of elements with much greater mass than just hydrogen. Also these planets and debris fields probably wouldn't emit much in the way of radio energy and if planets existed in sufficient numbers would increase the mass of the galaxy by quite a lot.

A:
The mass of all the planets in our solar system is about 0.1 percent of mass of the Sun, so if our solar system is typical, the total mass of planets in the galaxy is small compared to that of stars.

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