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Temperature within the epicenter of a Black hole.

  1. Aug 29, 2011 #1
    I've been curious for some time on what the temperature within the epicenter of a black hole. Due to its ultra high density one would imagine it would be extremely hot. However I began to wonder how time or rather the lack of it would affect temperature which is usually generated through friction. If you are in an envirement that has no time whatsoever. How would you have temperature or for that matter would any matter within such a timeless zone have any form of information or would it be similar to a Bohr's Einstein condensate.

    Would it not seem more probable that temperature within a timeless envirement be zero ?
    If something such as temperature has any meaning in such an envirement.
     
  2. jcsd
  3. Aug 30, 2011 #2
    I think you might be confused as to what temperature really is. When looking at temperature, you are strictly taking an average measure of the kinetic energy of the particles of a given substance.
    Stephen Hawking showed that black holes should radiate uniformly, like a blackbody, and like all blackbodies, this radiation would be tied directly into its temperature.

    I guess the simplest way to answer your question would be to use thermodynamics, which says, if you have a black hole, which is taking up alot of entropy from things around it (think of it as eating up nearby energy and disorder) it cannot have no energy or no disorder itself, because that would violate the second law of thermodynamics. So it must definitely have some finite temperature.
     
  4. Aug 30, 2011 #3
    Not sure that helps, Energy is the ability to do work or bring about change, Thermodynamics is the study of such change. In a timeless location energy cannot work or bring about change as there is no time for that change to take place, Therefore no work is done, No exchange of energy is possible, No vibration, frequency and also no entropy, A timeless mass cannot change, it cannot grow or shrink, Particles will not bumb into each other to transfer energy etc. I'm only remotely familiar with Stephen Hawkings radiation but I do recall he showed in a quantum world black holes can shrink however I am not familiar with his formulas used to arrive at this. Many concepts in quantum mechanics still elude me particularly those related to M theory, string theory etc.
    My main problem is what happens to the physics of a timeless location can matter or energy even exist in such an improbable point.

    "think you might be confused as to what temperature really is. When looking at temperature, you are strictly taking an average measure of the kinetic energy of the particles of a given substance"

    The kinetic energy of an object is the energy which it possesses due to its motion.[1] It is defined as the work needed to accelerate a body of a given mass from rest to its stated velocity. Having gained this energy during its acceleration, the body maintains this kinetic energy unless its speed changes. The same amount of work is done by the body in decelerating from its current speed to a state of rest.

    If there is no time then there cannot be motion as there is no time for motion hence no kinetic energy.

    Second law of thermodynamics: Heat cannot spontaneously flow from a colder location to a hotter location.
    The second law of thermodynamics is an expression of the universal principle of decay observable in nature. The second law is an observation of the fact that over time, differences in temperature, pressure, and chemical potential tend to even out in a physical system that is isolated from the outside world. Entropy is a measure of how much this process has progressed. The entropy of an isolated system which is not in equilibrium will tend to increase over time, approaching a maximum value at equilibrium.

    In classical thermodynamics, the second law is a basic postulate applicable to any system involving heat energy transfer; in statistical thermodynamics, the second law is a consequence of the assumed randomness of molecular chaos. There are many versions of the second law, but they all have the same effect, which is to explain the phenomenon of irreversibility in nature


    my question here is what if there is no time I copied this from wiki regarding the second law of thermodynamics as well as a couple other paragraphs as a time saver lol.
    in this case there is no decay as there is no time for any of the mentioned, decay, heat energy transfer or any of the other processes describing an evening out of the isolated system as there is no time for the system to even out.
    For that matter time being a measure of change, a time of zero = no change neither matter or energy/radaition cannot fall into such but merely on the surface, at such a point borderline to where time once again starts.

    Please keep in mind I am not a physicist however I have always enjoyed learning and this is one of those subjects that has always peaked my interest lol.
     
    Last edited: Aug 30, 2011
  5. Aug 30, 2011 #4
    I think what you are asking now is not testable. You can understand that there is an event horizon that acts as the limit in terms of actually being able to observe things about the black hole. You cannot make observations about the actual centre of the black hole (the singularity where an observer in that frame might experience a breakdown in time), because going in to get the measurements ensures that you can never send the measurements back out again.
     
  6. Aug 30, 2011 #5
    Definetely agree on your points, It would be impossible to take measurements on such lol.
    Not only because the information cannot leave but also there is no time to get the measurements. However most of what I've read and seen on programs usually describe the core of the blackhole as billions/millions of degrees, I can easily see the event horizon being such, however the area within (possible point of no time), Would not have a temperature as our definitions of such describe. Granted the potential energy is there and obviously the mass must be there. But because there is no time/change I feel that its temperature at that point would be zero or as near to as possible
     
  7. Aug 30, 2011 #6

    K^2

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    Epicenter is a projection of center onto some surface. It is a commonly misused word. I think you just mean center.

    I don't think the singularity of a Schwarzschild black hole can have a temperature. Temperature is a property of energy distribution. I don't see how that thing can have a distribution. On the other hand, I don't see a reason to assume that this is a valid description of the black hole.

    As far as thermodynamics is concerned, none of it really matters, since from perspective of the rest of the universe, anything that has ever fallen into the black hole is still above the event horizon, including the star that collapsed to form the black hole.
     
  8. Aug 30, 2011 #7
    Are you referring to no information of the original matter/energy falls beyond the event horizon ? The way I originally read this statement led me to think you were describing that matter itself would not fall beyond the event horizon. However I think your referring to Black hole information loss paradox. Please clarify, I understand the singularlty can be described as having infinite density at zero volume according to some articles I've read but could never wrap my mind around that concept of something having infinite density but no volume.
     
    Last edited: Aug 30, 2011
  9. Aug 31, 2011 #8

    K^2

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    Having infinite density and volume would be bad. Very, very bad. An infinite density should only exist in zero volume, so that the overall mass is finite.

    Matter itself is still falling from perspective of any external observer.
     
  10. Aug 31, 2011 #9
    Ah gotcha, Thanks for the clarification.
     
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