How do we know that dark matter exists?

By precisely measuring the distribution of X-rays from the hot gas, the astronomers were able to make the best measurement yet of the distribution of dark ... http://starchild.gsfc.nasa.gov/docs/StarChild/questions/question59.html - 9k

StarChild: Multidisciplinary Universe Activities: Puzzle

as a black hole's 12. Quasars emit many different types of energy such as X-rays and rays. Across. 3. Space objects believed by many ... http://starchild.gsfc.nasa.gov/docs/StarChild/universe_level2/activity/puzzle.html - 20k

Radar

modern method of measuring distances is based on the fact that light (whether in the form of radio waves, microwaves, visible light, or X-rays) travels with a ... http://starchild.gsfc.nasa.gov/docs/StarChild/questions/radar.html - 5k

Dr. Stephen Hawking

His most important discovery so far is that black holes emit X-rays and gamma-rays that can be detected by special scientific instruments. ... http://starchild.gsfc.nasa.gov/docs/StarChild/whos_who_level1/hawking.html - 7k

StarChild: Quasars

The word quasar is short for quasi-stellar radio source. Quasars give off radio waves, X-rays, gamma-rays, ultraviolet rays, and visible light. ... http://starchild.gsfc.nasa.gov/docs/StarChild/universe_level1/quasars.html - 8k

StarChild: Answer to the Stephen Hawking Question

Dr. Hawking discovered that black holes emit radiation (X-rays and gamma-rays) which scientists can detect and use to study the black hole. ... http://starchild.gsfc.nasa.gov/docs/StarChild/whos_who_level1/hawking_answer.html - 4k

Subrahmanyan Chandrasekhar

This satellite orbits Earth. It studies the universe by looking at X-rays from space. It is looking for clues about the past and the future of the universe. ... http://starchild.gsfc.nasa.gov/docs/StarChild/whos_who_level1/chandra.html - 7k