Q&A: X-ray Astronomy
Because much of the
matter in the universe cannot be seen by any other telescope.
X-ray telescopes are the only way we can observe extremely hot
matter with temperatures of millions of degrees Celsius. It
takes gigantic explosions, or intense magnetic or gravitational
fields to energize particles to these high temperatures. Where
do such conditions exist? In an astonishing variety of places,
ranging from the vast spaces between galaxies to the bizarre,
collapsed worlds of neutron stars and black holes.