Slashdot is powered by your submissions, so send in your scoop

 



Forgot your password?
typodupeerror
Check out the new SourceForge HTML5 internet speed test! No Flash necessary and runs on all devices. ×
Math Space Science

Physicist Claims Black Holes Mathematically Don't Exist 356

Koreantoast writes: Black holes, the stellar phenomena that continue to capture the imagination of scientists and science fiction authors, may not actually exist. According to a paper published by physics professor Laura Mersini-Houghton at the University of North Carolina and Mathematics Professor Harald Pfeiffer of the University of Toronto, as a collapsing star emits Hawking radiation, it also sheds mass at a rate that suggests it no longer has the density necessary to become a black hole — the singularity and event horizon never form. While the arXiv paper with the exact solution has not yet been peer reviewed, the preceding paper by Mersini-Houghton with the approximate solutions was published in Physics Letters B.

"I'm still not over the shock," said Mersini-Houghton. "We've been studying this problem for a more than 50 years and this solution gives us a lot to think about... Physicists have been trying to merge these two theories – Einstein's theory of gravity and quantum mechanics – for decades, but this scenario brings these two theories together, into harmony."
This discussion has been archived. No new comments can be posted.

Physicist Claims Black Holes Mathematically Don't Exist

Comments Filter:
  • by pushing-robot ( 1037830 ) on Wednesday September 24, 2014 @11:49AM (#47984221)

    Respectable mad scientists have known for years that supposed 'black holes' are really just wormholes to the goatee universe.

  • by Anonymous Coward on Wednesday September 24, 2014 @11:50AM (#47984229)

    IAAASBH (I am an astrophysicist studying black holes): Yeah, um, no.

    • by Anonymous Coward on Wednesday September 24, 2014 @12:20PM (#47984683)

      Perhaps you're observing phenomenon that appear to be Black Holes but are really gravstars or other normal stellar phenomena that don't require exotic and contradictory explanation and you don't realize it.

      After all, just because you learned something growing up as a child doesn't mean it's true.

      You are after all doing remote observation on objects that are 100's to billions of light years away.

      • by Moof123 ( 1292134 ) on Wednesday September 24, 2014 @01:09PM (#47985287)

        "After all, just because you learned something growing up as a child doesn't mean it's true."

        Or perhaps the sensationalist non-peer reviewed paper making wild claim about the nature of the universe will wilt under scrutiny?

        I generally don't throw out everything I learned as a child the first time I hear a contradictory claim, I perk up my spidey sense and look for extra info pro/con and decide if it is time to adjust my mental model of the world around me. Often it turns out that wild claims are a load of bunk from crackpots (shocker!).

        My favorite early formative experience like this from my teenage years was a guy at a cafe who, after overhearing my step-dad and me talking engineering, and posed a riddle about a piece of string wrapped around the earth, and if by adding some length (I forget now) while evenly raising its height above the ground, could a poodle walk under it? Turns out that simple analysis showed his answer was completely wrong and BS (he claimed it took miles, while it takes 2*pi*poodle). My take-away was to be skeptical of crack-pots making wild claims about the world, they are often either idiots or wrong (especially if they clearly have an anti-science agenda).

    • by kruach aum ( 1934852 ) on Wednesday September 24, 2014 @12:30PM (#47984809)

      No, you indirectly observe what are supposed to be black holes, or better yet, you directly observe instrument readouts that you interpret as indicating the existence of black holes. If this paper is correct, perhaps a different interpretation is in order, and exciting science can be done.

    • by bobbied ( 2522392 ) on Wednesday September 24, 2014 @12:30PM (#47984819)

      IAAASBH (I am an astrophysicist studying black holes): Yeah, um, no.

      So... The science is settled then? OK...

    • by fermion ( 181285 ) on Wednesday September 24, 2014 @12:37PM (#47984903) Homepage Journal
      Black holes are mathematical constructs that allow us to explain certain phenomena. We make certain observations the are consistent with the mathematical construct and say it is a black hole. This is not far removed than saying wood has fire in it because fire comes out of wood. For a certain cases, that is a reasonable explanation and a reasonable way to look at the situation. However there are issues if one is going to talk about more objective science. The same issue occurs with dark matter, which is a critical part of explaining the observable universe, but also has issues.

      I don't think we can just assume something is fact because it fits with what we know right now. Modern physics was built on quashing the assumptions that infinities and infinitesimals exist. We cannot go arbitrarily fast, and we cannot chop things up infinitesimally small, or measure to an arbitrary accuracy. These ideas were built in to classical mechanics as deeply as black holes.

      To be clear I am not saying that black holes do not exist and what we observe and call black holes are not black holes. Just that when we are dealing with artifacts of mathematical models, time could identify them more as artifacts of the model rather than the most useful representation of the observable universe.

    • by Geoffrey.landis ( 926948 ) on Wednesday September 24, 2014 @12:40PM (#47984957) Homepage

      The headline-- black holes don't exist-- is at odds with the actual article.

      The article doesn't say the mathematicians said that black holes don't exist: it says they showed black holes aren't formed by the collapse of massive stars. Black holes such as the ones at the nuclei of galaxies may very well be formed by other processes.

      --even if it were true that black holes don't exist, by the way, it doesn't solve the problem of the incompatibility of general relativity with quantum mechanics. At best it would solve the black hole information paradox; but since it still incorporates Hawking radiation in the solution, it doesn't even solve that.

      • by lgw ( 121541 )

        Specifically, the researcher is saying that the process of stellar collapse sheds so much mass via hawking radiation that there's not enough left to form a black hole. Given this is a fresh paper, and at odds with astronomical observations, I'm skeptical.

        • by Immerman ( 2627577 ) on Wednesday September 24, 2014 @01:51PM (#47985759)

          How is it at odds with observations? We've (indirectly) observed some of objects consistent with our theories of how black holes would behave, but to the best of my knowledge we've never observed the *formation* of such an object.

          Moreover, as I recall there is more than a little controversy as to whether supermassive black holes could actually form and grow in a manner consistent with prevailing theory, as opposed to having been formed in the early moments of our universe, or through some yet-to-be-theorized process. And if the biggest candidates couldn't actually form according to our theories, then I see no reason to assume their much smaller bretheren couldn't be formed throgh the same alternate process, whatever that might be.

          It could even be, as the headline deceptively states, that back holes don't actually exist and our candidate objects are something else that only superficially resembles them at phenominal distances, but that certainly wouldn't be my first assumption.

          • How is it at odds with observations? We've (indirectly) observed some of objects consistent with our theories of how black holes would behave, but to the best of my knowledge we've never observed the *formation* of such an object.

            The headline-- Black holes don't exist-- is at odds with our observations: we see things that appear to be black holes.

            The actual summary is not at odds with our observations: the summary says that stellar collapse doesn't form black holes, and we don't have observations to say know how the black holes we seem to be observing were formed.

            Now, you could go on and ask whether the things that we see which we are interpreting as black holes might be something else. But that would require a new theory that coul

    • by suutar ( 1860506 )

      Based on the arxiv summary, it sounds less like "we don't think black holes exist" than like "when we add hawking radiation to our model, it doesn't collapse down that far, wtf", leading to (in my mind) the questions "well, do we see anything that looks like what this model is saying" and "in that case where do the things that look like black holes come from". (I suspect the answer is going to be "there's a bug in this model right _here_", but we shall see :)

      If you happen to read the whole paper and feel li

  • Hmmm ... (Score:5, Interesting)

    by gstoddart ( 321705 ) on Wednesday September 24, 2014 @11:51AM (#47984241) Homepage

    So, what are those big honking things [astronomy.com] seeing [physicsworld.com]?

    Is this a case where something has been mathematically proven to not exist after it's been observationally confirmed?

    • Pfft, my psychiatrist does that all the time.

    • Re:Hmmm ... (Score:5, Funny)

      by Mordok-DestroyerOfWo ( 1000167 ) on Wednesday September 24, 2014 @11:57AM (#47984327)
      Something about man proving that black is white and getting himself killed at the next zebra crossing?
    • by Lucas123 ( 935744 ) on Wednesday September 24, 2014 @11:57AM (#47984333) Homepage
      She's not saying the things are not "very very dense" rather just that they never collapse further than the state that gravity can overcome the speed of light. I believe she's saying a black hole's mass would be "evenly" (or not) spread out over the volume encompassed by the event horizon, rather than in a singularity.
      • by HangingChad ( 677530 ) on Wednesday September 24, 2014 @12:12PM (#47984565) Homepage

        just that they never collapse further than the state that gravity can overcome the speed of light.

        It sounds like a new term like "black star" rather than "black hole" might be in order. Because the stars at the center of our universe are orbiting around something really heavy that doesn't emit any visible light.

        If I'm reading this right there's something really big and heavy there, we just can't see it.

      • If the even horizon was actually the body of the object then I don't believe we would be seeing some of the effects we see. Not being an astrophysicist I can't put it in words but there are observed phenomenon relating to black holes that are tied to matter collapsing into the singularity from the event horizon (at least that's our current understanding) if the event horizon is the edge of the body then these phenomenon wouldn't happen.

        In all likelihood there is going to be a review that finds some mistake

      • by mark-t ( 151149 ) <markt AT nerdflat DOT com> on Wednesday September 24, 2014 @01:06PM (#47985249) Journal
        It's not that gravity "overcomes" the speed of light, per se... but the fact that light always travels in a straight line, and that gravity can actually bend space, affecting what straightness actually is in that reference frame. Black holes, therefore, would bend space within a volume of space referred to from outside of it as their event horizon such to an extent that any straight line within the volume defined by the event horizon never actually leaves that volume.
    • by TWX ( 665546 )
      My expectation is that the true nature of the underlying physics is what's in question, rather than the observation of some form of stellar body, however technically indirect as it would have to be in this case.
    • Re:Hmmm ... (Score:5, Interesting)

      by i kan reed ( 749298 ) on Wednesday September 24, 2014 @11:59AM (#47984359) Homepage Journal

      And there's also a reallllllllllllly telling quote in the actual paper [sciencedirect.com] I'm still reading to make sure I understood the context right, but,

      Consider a spherically symmetric, uniform density, perfect-fluid star, undergoing gravitational collapse. The stress energy tensor of the fluid is ...

      Looks like a hell of assumption to make about stellar density. We know the cores are way more dense than the rest of the star, that's the magic that makes the fusion happen.

      Now if this assumption is qualified and addressed later in the paper, I'll be guilty of not being careful enough, but I haven't found that clue yet.

      • the core of a normal star. Once gone nova, is there really much difference in the remnant white drwarf or neutron star? A star does not go from normal to black hole in an instant.

      • Re:Hmmm ... (Score:4, Informative)

        by i kan reed ( 749298 ) on Wednesday September 24, 2014 @12:25PM (#47984737) Homepage Journal

        A follow up. The abstract for the second paper is linked in the summary, and the conclusion of the paper I'm referencing above suggests that the second paper(which we only have the abstract to) will attempts to address some of the concerns of simplistic assumptions. I think I'd need to do some really hard math, and pay for the full paper to determine if I personally agree with it justifying those assumptions, which I think is better left to experts who aren't supposed to be doing some programming right now.

      • That was the earlier paper. In this paper, they use a more realistic model and numerical simulation. They still get a result that doesn't include an actual singularity.
      • by drerwk ( 695572 )
        Read the conclusion where the author directly addresses your concerns. But, I will also point out that at the stage of collapse the authors are talking about the star more closely resembles a neutron star rather than a hydrogen fusing star. Because a neutron star is supported by Pauli exclusion, it seems to me that the density may well be close to constant through out a majority of the star.
    • Re:Hmmm ... (Score:5, Interesting)

      by medv4380 ( 1604309 ) on Wednesday September 24, 2014 @12:11PM (#47984559)
      Since Hawking Radiation hasn't been observed in any repeatable experiment, and the universe is too warm to tell it apart from the background radiation if black holes do emit it I'd say that the assumptions could be wrong. Since the claim is that the event horizon never forms it's claiming that those black things in the center of galaxies don't exist, or should be just above the minimum to be a black hole. I'd say this is actually a hit against Hawking Radiation, or one of the other assumption, and not a hit against Black Holes.
    • by wbr1 ( 2538558 )
      Maybe something else? If her the observations we have still fit her calculations, then it is a valid theory.
    • So, what are those big honking things [astronomy.com] seeing [physicsworld.com]?

      Don't know. Sometimes you think you've seen one thing but then it turns out it's something entirely different. That's the joy of learning. Our understanding (generally) improves over time.

      Is this a case where something has been mathematically proven to not exist after it's been observationally confirmed?

      Could be. Or not. I don't have the background to know if this paper is factually correct or not. But that's the thing about radio astronomy regarding things massively distant... you're not actually observing anything. You're taking in massive amounts of data then interpreting it. Sure, your eye does that when you l

    • by idji ( 984038 )
      they are not denying that such supermassive black objects exist, they are questioning whether they are singularity "holes" with an event horizon.
    • If black holes don't exist, then the answer is "something other than a black hole". I would say that things as massive as black holes have been observationally confirmed. Whether these things have been observed to have all the properties of the traditional mathematical model of a black hole is a different claim.

      I'm skeptical of the claim that "black holes don't exist", but saying "we observed them" is begging the question, because it presupposes that the observed phenomena was a black hole.

  • by ArcadeMan ( 2766669 ) on Wednesday September 24, 2014 @11:54AM (#47984287)

    A collapsing star emits Hawking radiation.

    If it emits Hawking radiation as it's collapsing, it doesn't become a black hole, it becomes a Hawking hole.

  • by RockGrumbler ( 1795608 ) on Wednesday September 24, 2014 @11:54AM (#47984289) Homepage
    I felt a great disturbance in the Force, as if millions of CGI Artists for science documentaries suddenly cried out in terror, and were suddenly silenced.
  • "into harmony" (Score:3, Insightful)

    by oodaloop ( 1229816 ) on Wednesday September 24, 2014 @11:55AM (#47984311)

    this scenario brings these two theories together, into harmony."

    and into direct conflict with observations. I'm going to guess your math is wrong, not that black holes don't exist.

    • As the scientific method dictates, we should send these scientists into a black hole to verify the theory.

      • As the scientific method dictates, we should send these scientists into a black hole to verify the theory.

        No, for this kind of testing you start with a lesser, more expendable species ... I suggest politicians and lawyers.

        • by qwijibo ( 101731 )

          Do you realize how far the nearest black hole is and how long it would take to get there? What do you think the scientists are going to eat on the trip? Politicians and lawyers seems like a good compromise. Those atoms will never return to earth and I think we can live with that.

    • Re:"into harmony" (Score:5, Interesting)

      by RobinH ( 124750 ) on Wednesday September 24, 2014 @12:13PM (#47984587) Homepage
      We have two theories: quantum mechanics and relativity, and they disagree about what happens when really massive stars collapse (or relativity predicts a singularity and quantum mechanics doesn't have much to say about what happens at those energies). The relativity answer seems impossible because when you get infinity out of an answer in physics, your math is probably wrong. Quantum mechanics only covers the 3 other forces, not gravity. So really we know that we probably don't know what's going on with this phenomenon. The term "black hole" is a little bit like "dark matter". It's a placeholder for what we don't know. We have observed evidence that there are extremely heavy and dense objects affecting nearby stars, but we can't observe them directly. So, what we've observed is not necessarily exactly what relativity predicts is there. This paper is offering a different theory (which may or may not be more correct).
  • by war4peace ( 1628283 ) on Wednesday September 24, 2014 @11:56AM (#47984317)

    In the true spirit of /. I only read TFS but from it I see that only the "collapsing star" method of creating a black hole is covered. So there must be other methods for obtaining a black hole which won't violate mathematical simulations.

  • ... slashdot doesn't exist, either as it fell below the noise level of web traffic long ago. But yet here we are using it.
  • They look lke black holes from the outside, but are not singulaties. Matter collpses to highest quantum density possible- one plank mass per plank volume- bbut not infinitely small.
  • by NEDHead ( 1651195 ) on Wednesday September 24, 2014 @12:34PM (#47984863)

    It is generally posited that a singularity is the result of a gravitational collapse resulting in a black hole. However an event horizon will form whenever sufficient mass density occurs, thus a 'black hole'. If the contention is that the Hawking radiation dissipates the mass before the singularity forms, so be it. Does not mean no black hole, just no singularity.

    I have not read the article, so I don't know if this is reflective of her contention, however:

    Imagine 2 observers, 1 falling into the black hole, one with great patience a safe distance away. Over time the distant observer will see the black hole eventually become isolated and cease to accumulate new mass (trillions of years perhaps). Thereafter, Hawking radiation begins to dominate and the black hole goes on a diet, eventually going out of existence with a hot bang.

    Meanwhile the more adventurous observer is falling toward the postulated center of the black hole, but is experiencing greater and greater time dilation relative to the low density external universe. Thus at some point, before reaching the singularity state, the observer 'sees' the entire future of the external universe, including an ever increasing flood of Hawking radiation that results in the black hole evaporation. So incoming matter never gets to infinite density, no singularity occurs because the evaporation happens on a different time scale than the collapse. Black hole? Yes, Singularity? No

    If this is not the equivalent of the cited paper, I am free to go to Oslo at any time.

    • Not according to General Relativity (without quantum mechanical consideration), a (gravitational) event horizon MUST have a singularity inside, proven by Hawkings and Penrose in the 1960s.

      • Not have, lead to.. which allows time for other events to intervene.

        • eh, don't understand your first phrase.

          in classic GR nothing can intervene once the event horizon forms, all matter inside MUST wind up in singularity in finite time, and there is no infinite force that can keep that from happening.

          • 'Lead to' implies something that occurs after passage of (local) time.

            Sure, and in classical GR you end up dividing by zero. The point I was making was that 'finite time' is not zero time, and the disparity in the rate of time inside the event horizon vs far away allows plenty of time for quantum effects in the form of Hawking radiation to intervene and dissipate the black hole before the posited singularity come into existence. Since the events transpire over finite time, no infinite force is required.

      • And the 'without quantum mechanical consideration' is exactly ignoring Hawking radiation

        • Are you clear this theory says no event horizons and no singularities either? Only hawking radiation in area with strong enough gravity to lose gravitational energy by affecting spontaneous particle pair formation. Hawking radiation in case of black holes existing do not prevent singularity from forming as it only exists outside the event horizon. It does not provide a mechanism for changing space-time geodesic inside event horizon, which must end on singularity. If quantum mechanics does prevent singul

  • It wasn't that long ago that the scientific community claimed that a common bumble bee could not fly according to known laws of science. Black holes seem to be present and common place. When observations do not match equations bet your dime on the observations.
    • The scientific community claimed no such thing. Random idiots did though. Says Wikipedia:

      The flight mechanism and aerodynamics of the bumblebee (as well as other insects) are actually quite well understood, in spite of the urban legend that calculations show that they should not be able to fly. In the 1930s, the French entomologist Antoine Magnan, using flawed techniques, indeed postulated that bumblebees theoretically should not be able to fly in his book Le Vol des Insectes (The Flight of Insects).[159] Magnan later realized his error and retracted the suggestion. However, the hypothesis became generalized to the false notion that "scientists think that bumblebees should not be able to fly".

  • Clearly the only way to solve this issue is to send a manned expedition into the black hole to see what we find!
  • http://www.cnet.com/news/stephen-hawking-declares-there-are-no-black-holes/ [cnet.com]

    Just means that the choice of word should change:

    His precise words were: "The absence of event horizons mean that there are no black holes -- in the sense of regimes from which light can't escape to infinity."

    It seems clear. There are no forever and ever holes of blackness. There is always the chance that light might emerge.

    Hawking continued, however: "There are however apparent horizons which persist for a period of time. This suggests that black holes should be redefined as metastable bound states of the gravitational field."

  • To take what is probably the strongest example of an observed phenomenon that can be explained as a black hole and not much else. Even Hawking gave in and paid off his bet with Kip Thorne.

  • by cb123 ( 1530513 ) on Wednesday September 24, 2014 @02:53PM (#47986419)

    While this calculation may help convince about some aspects of some arguments, it isn't necessary for the headline claim. There was always an old issue non-formation (or more accurately partial realization in finite-time or general paradox/etc) because of the coordinate singularity at the event horizon (time slows to a stop). There is even a book called Frozen Star by Greenstein from the 1980s if you are interested in the history of this.

    The reason what the article of this thread says may cause controversy or confusion is because of the cultural way the resolution of the original issue got converted into a "talking point"/recurring example/"de-confused". In free falling coordinates, crossing the event horizon is no more special than walking across Earth's North Pole. There is no "problematic" infinity until the actual center point (which is what the Hawking-Penrose singularity theorem is about, but that theorem in essence assumes non-evaporation). That theorem itself was in response to speculation of some process intervening to "bounce" collapsing stars and censor black holes from the universe.

    All these statements are fine and still correct as far as they go, but one has to be careful about the background assumptions embedded in analyzing things in free fall coordinates. A long history of poo-poo'ing the coordinate singularity or some hypothesized bounce process as "unreal" or "unphysical" led to a tradition of always analyzing things in free fall coordinates (as the arXiv paper in the OP does!). The validity of this transform does have implicit requirements, just not in the pure math of the general relativity transforms but in the physical context. E.g., it requires an infinite background future (i.e. no Big Crunch) which seems to be implied by data these days but was in great doubt for decades. It also assumes a non-evaporating situation which has been in doubt since the mid-1970s with Hawking Radiation.

    Here's the important point which I cannot emphasize enough: WHAT ACTUALLY TRANSPIRES IS REFERENCE-FRAME INDEPENDENT. At some (maybe far) future time, a mass concentration is either there or it isn't. Period. Reference frames change observed rates/the clocks/positions maybe but not the actual core situation. If a distant, non-freefalling observer can see a Black Hole evaporate to nothing in a finite-time, then at the end of the day [ or the hole ;-) ] it will have taken less time to evaporate than to form in both the freefalling frame and the distant observer frame. That is just another way of saying it just didn't finish forming. That's it.

    People have been speculating about micro-black holes evaporating into nothing ever since Hawking's initial result. In that light there is no news younger than 40 years old here.

    To be sure there are some specific dynamics to be modeled here and what this paper does is model them in free fall coordinates. All those details are surely important to pro physicists. The zinger headline of non-formation doesn't rely on such details. It only relies upon any mass-energy transfer from within the hole to a great distance away and enough time in the heat death to have evaporation be the dominant process (or else a small enough black hole that it doesn't need much time). Hawking Radiation is but one such process, though a theoretical one. Most think (on similar general theoretical grounds) that any quantum gravity will have ways for strong gravitational fields to decay. So, it seems likely that there will be some process, but sure, sure, evidence is needed, too.

    Logically, though, reference frame independence of what actually happens means that any argument against non-formation is translatable to an argument against Black Hole decay. Contrapositively, any argument for black hole decay is an argument for only incomplete black hole formation. There may be possible glitches in last-moment of existence type stuff, but that truly is blind-leading-the-blind territory. I actually tried to raise this in 1988 with my freshman relativity professor but I don't think he understood my point and he mostly poo'poo'd about how Hawking Radiation would break down at the last moment of decay or something.

  • by sexconker ( 1179573 ) on Wednesday September 24, 2014 @05:18PM (#47988115)

    Black holes as we conceive of them now would actually be easy to see.

    Light originating from behind the black hole (from the perspective of the viewer), traveling in a direction toward the black hole (but not intersecting the event horizon), would be bent by the black hole. The result would be extreme gravitational lensing. When looking at the black hole, the effect would range from a general increase in brightness around the black hole, to an extreme brightness appearing to originate from the location of the black hole.

    Objects of such mass and density have not been found. We have speculated that they exist at certain places, but we have not seen the requisite lensing effects akin to a kid using a magnifying glass outside (either just looking at shit or using it to burn shit).

    Black holes, with the requisite lensing effects may exist, but they'd be easy to spot. What we seen so far, and have labeled as black holes, cannot be of the size and mass we think they are.

  • by Required Snark ( 1702878 ) on Wednesday September 24, 2014 @06:02PM (#47988441)
    This proposal is related to the loop quantum gravity [wikipedia.org] view of physics, which is an alternative to string theory.

    The authors propose a singularity is not created when a black hole collapse occurs. Instead, the suggest that the material falling into the gravity well forms a "Planck star". The mass does not disappear into a singularity, but remains as a form of matter compressed to the Planck scale. The Planck pressure (my term) stops the gravitational collapse, so no infinite mathematical feature is involved.

    A Plank star has very similar characteristics to a conventional black hole. It has a Schwarzschild radius, so matter and energy are swallowed up in the same way. The difference is what happens inside the Schwarzschild radius and the long term fate of the star.

    Two effects come into play: time dilation and Hawking radiation. Because of the immense gravity, time dilation makes events inside the Schwarzschild radius appear to take billions of years to the outside observer, although the happen rapidly in the frame of reference of the Planck star. As in-falling matter hits the Planck matter core, it bounces back. It does not simply collect at the core.

    Additionally, Hawking radiation occurs. This means that energy can be released outside the Schwarzschild radius, which allows the star to loose mass. In this theory, about a third of the mass can escape via this mechanism. However, this process also takes a long period because of time dilation. (There is more complexity to this, but since I'm not certain how it works I'll not try and describe it.)

    Eventually the radius of the expanding Plank star matter and the Schwarzschild radius intersect, and from the point of view of the external observer the formerly "black" hole explodes. This is different then the long term evolution of a classical black hole, which looses most of it's mass via Hawking radiation. The final evaporation of a classical black hole is not a big explosion since the final mass is relatively small, and no matter how big the black hole was, the final bang is the same size. For a Planck star, the size of the explosion depends on the mass inside the Schwarzschild radius.

    This theory has some very nice properties. First, there is no infinitely dense matter. Classical black hole models have been trying to grapple with this issue for a long time. Also, since the final explosion can be massive, it could be the source of very high energy cosmic rays. Some have already suggested that gamma ray bursts may be the visible result. The theory predicts that the explosion can take about 14 billion years to occur to an external observer, so that fits in with the current age of the universe. Note that there are testable features relating to cosmic rays and other radiation coming from Plank stars, so observational verification is possible.

    An important part of the theory is that it resolves the black hole information paradox [wikipedia.org]. According to this article at Phys.org [phys.org]

    Rovelli and Vidotto wonder why this couldn't be the case with black holes as well—instead of a singularity at its center, there could be a Planck structure—a star—which would allow for general relativity to come back into play. If this were the case, then a black hole could slowly over time lose mass due to Hawking Radiation—as the black hole contracted, the Planck star inside would grow bigger as information was absorbed. Eventually, the star would meet the event horizon and the black hole would dematerialize in an instant as all the information it had ever sucked in was cast out into the universe.

    This is potentially a big deal. If true it solves some troubling theoretical problems and man tie black holes and cosmic rays together. It would also present a huge challenge to string theory, because it gives credence to loop quantum gravity.

The test of intelligent tinkering is to save all the parts. -- Aldo Leopold

Working...