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The Question
(Submitted March 16, 1998)
Why does accretion of matter onto black holes make them luminous?
The Answer
As the matter falls into the black hole, and before it enters the
event horizon, it turns gravitational potential energy into kinetic
energy and so picks up a lot of speed. Some of this energy is then
converted into light and other electromagnetic energy. But the
most luminous part of black holes are the jets of accelerated matter
that are emitted from the polar regions. These are probably generated
because of the very strong rotating magnetic field that is usually
associated with Black Holes.
You should also look at:
http://imagine.gsfc.nasa.gov/docs/science/know_l2/black_holes.html
for more information.
Thanks for your question.
Eric Christian
for Ask an Astrophysicist
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