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  1. Standard member max92
    let's play CHESS
    14 Sep '08 08:27
    Is it possible that a black hole is something that is traveling faster than the speed of light?
  2. Standard member sonhouse
    Fast and Curious
    14 Sep '08 10:41
    Originally posted by max92
    Is it possible that a black hole is something that is traveling faster than the speed of light?
    In a word. no.
  3. 14 Sep '08 10:44
    Originally posted by max92
    Is it possible that a black hole is something that is traveling faster than the speed of light?
    Has a black hole mass?
    Yes? Then it cannot travel faster than the speed of light.
  4. 14 Sep '08 14:47
    I saw in a documentary on TV that a blackhole is simply a mass so big that had a gravity so strong that it swallowed itself and eerything about it.

    Is this true?
  5. 14 Sep '08 15:18
    Originally posted by dannyUchiha
    I saw in a documentary on TV that a blackhole is simply a mass so big that had a gravity so strong that it swallowed itself and eerything about it.

    Is this true?
    This is one way of describng a black hole.

    The "it swallowed itself" part I don't like. Also "everything about it" is a bit vague.

    But approximately it is true.
  6. 14 Sep '08 19:25
    I tried to explain it with the little knowledge I have on this topic.

    Would you care to enlighten us with a better explanation? My field is chemistry, not physics so I may seem a little ignorant in this kind of conversation, although I like to contribute as best I can.
  7. Standard member Wheely
    Instant Buzz
    14 Sep '08 20:23 / 1 edit
    Originally posted by dannyUchiha
    I saw in a documentary on TV that a blackhole is simply a mass so big that had a gravity so strong that it swallowed itself and eerything about it.

    Is this true?
    it doesnt´t have to be big

    EDIT: Misread your post. You said mass so big, not physical dimensions. You are correct.
  8. Standard member adam warlock
    Baby Gauss
    14 Sep '08 20:45
    Originally posted by Wheely
    it doesnt´t have to be big

    EDIT: Misread your post. You said mass so big, not physical dimensions. You are correct.
    Actually the mass doesn't have to be big at all. All it takes is a small enough radius. For each mass, m, there is a radius, r, which makes the body become a black hole if the radius is as big or smaller than r. Even a spoon can become a black hole...

    Ps: For the case of the spoon at some point QM effects would have to be taken into account and things might not be so straightforward, but in the context of GR it is always possible for a body to become a black hole.
  9. 15 Sep '08 00:56
    Originally posted by adam warlock
    Actually the mass doesn't have to be big at all. All it takes is a small enough radius. For each mass, m, there is a radius, r, which makes the body become a black hole if the radius is as big or smaller than r. Even a spoon can become a black hole...

    Ps: For the case of the spoon at some point QM effects would have to be taken i ...[text shortened]... aightforward, but in the context of GR it is always possible for a body to become a black hole.
    If we take the spoon as example, what criteria must be met in order to become a blackhole?
  10. Standard member adam warlock
    Baby Gauss
    15 Sep '08 09:51
    Originally posted by dannyUchiha
    If we take the spoon as example, what criteria must be met in order to become a blackhole?
    One thing though: I forgot that while calculating the radius QM effects are already taken into account, so this gravitational collapse will be even stronger than the degenerate pressure cause by fermions.

    The radius is called Schwarzschild radius and is calculated by r=2Gm/c^2 where the letters have their usual meaning. Just for you to have an idea I'll do a calculus having in mind a person. So say that you weigh 90Kg your Schwarzschild radius will be 1.483173*10^-27m.
  11. 15 Sep '08 12:53 / 1 edit
    Originally posted by adam warlock
    One thing though: I forgot that while calculating the radius QM effects are already taken into account, so this gravitational collapse will be even stronger than the degenerate pressure cause by fermions.

    The radius is called Schwarzschild radius and is calculated by r=2Gm/c^2 where the letters have their usual meaning. Just for you to have an mind a person. So say that you weigh 90Kg your Schwarzschild radius will be 1.483173*10^-27m.
    Question: You say that if you press a human body (of 90 kg) to a sphere with only a radius of about 1.5*10^-27 - what do you get?

    Answer: Well, not less that 8 years of prison...
  12. 15 Sep '08 22:22
    Originally posted by adam warlock
    One thing though: I forgot that while calculating the radius QM effects are already taken into account, so this gravitational collapse will be even stronger than the degenerate pressure cause by fermions.

    The radius is called Schwarzschild radius and is calculated by r=2Gm/c^2 where the letters have their usual meaning. Just for you to have an ...[text shortened]... mind a person. So say that you weigh 90Kg your Schwarzschild radius will be 1.483173*10^-27m.
    Thanks for that example, it made the idea clearer to me.

    So, I guess that based on that equation, it is impossible that the blackhole is something traveling at the speed of light...
  13. Standard member adam warlock
    Baby Gauss
    17 Sep '08 16:56 / 1 edit
    Originally posted by dannyUchiha
    Thanks for that example, it made the idea clearer to me.

    So, I guess that based on that equation, it is impossible that the blackhole is something traveling at the speed of light...
    From prsent day knowledge it is important for a black hole to travel at the speed of light because it has mass, not because of the previous equation.

    If you are interested in superluminal movement I'd reccomend for you to do a google search on tachyons.

    And if you like discussing these themes please consider joining Club 39
  14. 17 Sep '08 17:08
    Originally posted by adam warlock
    From prsent day knowledge it is important for a black hole to travel at the speed of light because it has mass, not because of the previous equation.

    If you are interested in superluminal movement I'd reccomend for you to do a google search on tachyons.

    And if you like discussing these themes please consider joining Club 39
    Thanks. I just applied for this club, although where I can really contribute is on chemistry...
  15. Standard member adam warlock
    Baby Gauss
    17 Sep '08 17:30
    Originally posted by dannyUchiha
    Thanks. I just applied for this club, although where I can really contribute is on chemistry...
    Thanks for applying and give your contribute where you can.