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Question
If nothing escapes a black hole because of the extreme gravity, why do x-rays escape?
Hello,
Actually x-rays do not "escape" the black hole proper. In most cases, holes are collapsed companions to a large, normal star. What happens is that the outer gaseous material of the normal star is *sucked into* the black hole.
When the atoms of the condensing, compacting gas layers are triggered into excitation (by friction, collisions etc), x-rays are the byproduct. Thus, we infer the existence of black holes from the x-rays made possible by the sucked in gaseous material of the normal companion star.
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Answers by Expert:
Philip Stahl
Expertise
I have forty years of experience in Astronomy, specifically solar and space physics. My specialties include the physics of solar flares, sunspots, including their effects on Earth and statistics as applied to astronomical investigations.
Experience
Astronomy: more than forty years experience starting with construction of my own simple telescopes. Worked at university observatory in college, doing astrographic measurements. M.Phil. degree in Physics/Solar Physics and more than ten years as researcher.
Organizations
American Astronomical Society (Solar Physics and Dynamical Astronomy divisions), American Mathematical Society, American Geophysical Union
Publications
Solar Physics (journal), The Journal of the Royal Astronomical Society of Canada, The Proceedings of the Meudon Solar Flare Workshop (1986), The Proceedings of the Caribbean Physics Conference (1985). Books: 'Selected Analyses in Solar Flare Plasma Dynamics', 'Physics Notes for Advanced Level'.
Education/Credentials
B.A. Astronomy, M. Phil. Physics
Awards and Honors
American Astronomical Society Studentship Award (1984), Barbados Government Award for Solar Research
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