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Black Hole Radiation

  1. Jun 21, 2004 #1
    I read the book, "ABOUT TIME" by Paul Davies and I forgot how particles getting sucked into a black hole convert some of their mass in high energy radiation such as x rays and gamma radiation. I am not referring to Hawking radiation that holds up the second law of thermodynamics but the radiation of particles getting sucked in right at the event horizon. Any help would be greatly appreciated. Thanks...`
  2. jcsd
  3. Jun 21, 2004 #2


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    Charged particles, when accelerated, emit radiation. Stuff getting sucked into black holes gets speeded up, gets ionized, and then emits radiation as it further speeds up.
  4. Jun 22, 2004 #3

    Thank you for the info
  5. Jun 22, 2004 #4
    But why does this happen when they are accelerated?
  6. Jun 22, 2004 #5
    Mathman is right but this doesnt apply to the question, he explains only about how radiation (in the form of photons) is emitted from particles that are given high energy. When particles are given high energy the electrons go to an excited state, when they go back to the ground state, the electons emit a photon. This explains how particles emit radiation, but the question is about how patricles that get sucked into a back hole are CONVERTED into energy. This is the case of Einstein's equation, E=mc^2. Although im not too sure myself HOW is happens, but i do know it happens when particles are annihilated, which can happen when it is collided with anti-matter. There are other ways too to convert mass into energy, one very common way is nuclear fusion, which the sun does a lot of. When two protons are fused to make a helium nucleus, the nucleas will have less mass than the two protons separate. The extra mass is converted into enegry according to the equation. I dont know if that at all helps, since i didnt really answer ur question, but i'll keep in touch if i can further help.
  7. Jun 23, 2004 #6
    Last night I decided to look up how x rays were generated in machines to get a better idea of what I ws trying to ask. It seems that accelerating electrons bombarding matter somehow releases energy in the form of x rays. In x ray machines they use a strong electric field or a cathode ray tube to accelerate the electrons and make them strike a plate made of tungsten and this somehow releases energy. I am ASSUMING this energy comes from the addition mass that is added to the mass off an electron due to its acceleration and is somehow released as high energy radiation.
    I know how energy is released as photons strike an atom by causing the electrons to go into an ecited state and then returning to its original valence in turn releasing a photon (reflection) but as to how electrons striking a mass particle and releasing high energy photons still seem a little fuzzy to me but the pictue (in my mind) is starting to get clearer. I appreciate all your help:)
  8. Jun 23, 2004 #7
    What u say about the electrons being accelerated using a cathode ray tube is correct. BUT i really do not think that anything happens to the electron itself, because when the electron hits the tungsten, the electron transfers its kinetic energy to it, and im assuming therefore causing the tungsten to emit radiation, since giving it KE will make the tungten's eletrons to become excited. In fact thats how a TV works, its basicly a cathode ray tube guided by magnets which shoot the electrons onto the screen which has some special coding, the atoms of the coding get exited, and therefore emit light, which is what we see on the screen. The light emitted is what makes up the picture of what u see on TV. Although im not sure how the shape of the picture is made. I'm pretty sure that should help, if in any case im wrong, sorry, im not an expert on anything, im just a high school student very interested in astronomy/astrophysics/chemistry/physics, all that good stuff, lol. :P
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