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Black & White Holes

  1. Sep 16, 2006 #1


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    I believe that this post is mainly concerned with Astronomy, but if it should belong somewhere else then please forgive me.

    In laymans terms, a black hole is a collapsed entity with a gravitational pull so strong that nothing can escape it. Light, planets and stars are all pulled in. My first consideration is if whether time can also be pulled in or even be altered on the edge of the event horizon.

    Newtons thrid law states, again in laymans terms: "Every reaction has an equal and opposite reaction".

    So, if a black hole sucks everything in, why can't there be a white hole that spews everything back out? Light, planets and stars. Even time. This white hole is the equal and opposite reaction for a black hole. Say if the Earth was sucked into a black hole. We don't know what would happen. We could all be subject to spaghetification, which occurs on the event horizon, or we might not. But, if this hypothosis is correct, and there is a white hole at the "end" of the black hole, then when Earth is spewed back out it should contain all the same matter as it did when it crossed the event horizon, even if it has been altered through compression or some other means so that it no longer resembles its original form. This could be a form of time travel or long distance travel, assuming time is sucked in and spewed out of black and white holes respectivly and the matter spewed back out is still in the same shape and condition as it was when it crossed the event horizon.

    Any thoughts/criticism/backing-up of the mind of a wandering student would be greatly appreciated.
    Last edited: Sep 17, 2006
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  3. Sep 16, 2006 #2


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    AFAIK there is no evidence for white holes, a white hole is an example of
    where a theory can go astray.
  4. Sep 16, 2006 #3
    A good (but older) book on what you are talking about (although there is no such thing as a 'white hole') is called "Black Holes and Warped Spacetime". It explains much of this stuff in laymans terms.
  5. Sep 17, 2006 #4


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    Ah ok, I thought it was a long shot.

    Thank you for replying.
  6. Sep 17, 2006 #5

    George Jones

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    For more on white holes, see https://www.physicsforums.com/showthread.php?t=124111".

    By William J. Kaufmann III. Another excellent book by the same author is The Cosmic Frontiers of General Relativity.
    Last edited by a moderator: Apr 22, 2017
  7. Sep 18, 2006 #6
    Time is a concept. It is a unit for measuring distance over an equal meausrment of a moment. Time is just moment to moment progressions from distance to distance. Time does not slow down or speed up in a black hole, the only reason you might see someone fall into a black hole slower or faster is the fact that little if any light is even seen by an observer as the hole is sucking up the light that would allow you to see them falling in.

    if the earth stoped rotating around the sun time wouldnt stop only our calender for time, you would still age, you might die... but thats besides the point. Night and day is a constant so we divided it up evenly and put numbers on it. Time is not something you can travel forward or backwards in, we made it up.

    Time=a limited period or *interval*, as between two *successive events*, as definded and created by us.
  8. Sep 23, 2006 #7

    Gee, I always thought time was a dimension that changes depending on certian things like velocity, gravitation, etc. :uhh: I think you have a pre-Einstein view of time.
  9. Sep 24, 2006 #8

    Even post-Einstein, time is just really a measured interval between two successive events. It's just PERCIVED differently by people at different velocities/ gravitational field strength etc. (which effectivly makes it different for all observers) but that doesn't neccessarly mean that events occur in any different order or speed than if no one was observing them :surprised:
  10. Sep 25, 2006 #9
    Why would there be something spewing stuff out? A black hole is just compressed matter, right? It's not a law or theory, it's just something that happens.

    Or else you could say "if there are kids who spill their juice, there should be kids who's juice gets put back in its cup by itself".
  11. Sep 25, 2006 #10


    It can certainly be the case that the order of events is different from one observer to another. In relativity there is no sense of an observer independent order.
    Space and time are not absolute in relativity.
  12. Oct 14, 2006 #11
    Although white holes have no been spotted, how can we actually say that they do not exists? Think about this:

    The universe was once a singularity before the big bang. So, how did this singular object just appear magically from nothing, then go on to create atoms, and the universal expansion and all the laws of physics. Sounds a little odd. Now we know that Blackholes exists. My personal theory is: What if blackholes bend spacetime so much that it seperates the singularity into a different demension and causes another "big bang" in another universe?
    Last edited: Oct 14, 2006
  13. Oct 26, 2006 #12
    >> Newtons thrid law states, again in laymans terms: "Every reaction has an equal and opposite reaction". <<

    Just quickly back to your original question IXI, Newton's laws are very good for everyday life and things we observe around us. However, at extremities such as immense gravitational fields (eg those exerted on objects around black holes), Newton's laws fail, and we begin to use other theories (such as those famously devised by Einstein). This is especially applicable to the singularity point where the mass of the black hole is confined to infinite density and smallness. At singularity, all our physics laws fail and we have no means of describing or predicting events at this point.

    So even though you are correct in stating that every action has an equal and opposite reaction, that law fails on the extreme cosmic scale.

    Furthermore, I think the terminology of certain astronomical events and objects needs to be clarified so as to avoid confusion. "Black" holes are, as I'm sure everyone knows, not in fact black, so something opposite of a black hole would not necessarily be white. :smile:
  14. Oct 27, 2006 #13
    why wouldn't it be black? when something doesnt emit or reflect light, it's black?
  15. Oct 27, 2006 #14


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    Ah, but a BH "emits" thermally distributed Hawking radiation. It has a finite temperature, so it isn't truly "black".
  16. Nov 10, 2006 #15
    >> why wouldn't it be black? when something doesnt emit or reflect light, it's black? <<

    It could be green, but because it doesn't allow light to escape from its grip, we don't know. So if you like, a black hole could be any colour, but to us, it's just simply invisible.
  17. Nov 10, 2006 #16
    Then if black hole is so powerful, why doesn't it suck in Hawking radiation as well. I mean that radiation is, like light, an electromagnetic radiation, right?
  18. Dec 1, 2006 #17

    Chris Hillman

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    A black hole "sucks everything in"? No.


    This should be a FAQ, since I see it all the time. Black holes are not "cosmic vacuum cleaners"; they do NOT just suck in everything indiscriminately. Unless you get very close to a black hole, it doesn't really behave that much differently from any dark object with the same mass and angular momentum. For that matter, a light ray can come quite close to the event horizon of a black hole, without neccessarily falling in, in fact, depending on the details of the encounter, the light ray might very well wind around the hole several times and then "zoom off to infinity" again. Similar remarks hold for objects like stars, except that the strong tidal forces near a black hole are likely to pull part an ordinary star which comes too close.

    Actually, the same exact solution used to model (static) black holes in gtr can be used to construct a model of just such a "white hole". However, mainstream opinion in physics is that these models are unphysical because they tacitly invoke impossible (or at least highly implausible) boundary conditions. Remember, gtr is a (relativistic) classical field theory, and it is well known that classical field theories tend to admit "unphysical" solutions to their field equation unless you prohibit implausible boundary conditions. It is a bit embarrassing that such prohibition may require a certain amount of ad hoc argumentation, but this isn't really a defect of gtr; rather, it is a defect of the local field theory approach itself.

    Chris Hillman
  19. Jun 10, 2009 #18
    Hi. No one knows if time can be pulled in or not, but I wolud have to say no. I recomened that you go to online and find out for yourself. Now about the white hole: white holes cannot be possible and they cannot exist or be created. Why? Because a black holes gravity is not balanced or stable enough to create a connecting structure (wormhole) to another part of space/time.This is needed to create a white hole. Also, because of the shape and demntions of the black hole's core (the colappsed core of a star) is iregular, the gravitiational energy does not go beyond it, but circulates around it, threrefore not allowing a connecting structure to form. Those are just two of many resons why white holes cannot be possible. For more information about white holes, go to why white holes cannot exist, in the astrophysics section.
  20. Jun 10, 2009 #19
    I agree. No evidence has ever been presented on the subject.
  21. Apr 19, 2010 #20
    I suppose that the black hole is the reaction. Compacting an object into the size of its Schwarzchild Radius takes a lot of energy. Is this energy equal to that exerted by the black hole?
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