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Elementary particles are defined as particles having no internal structure - or at least none that we know. But we don't know, and maybe can never know, the internal structure of a black hole. So therefore as far as we're concerned they have no internal structure. Does that makes them (huge) elementary particles.

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    $\begingroup$ Possibly related: en.wikipedia.org/wiki/Black_hole_electron $\endgroup$ Commented Sep 9, 2016 at 21:43
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    $\begingroup$ But we don't know, and maybe can never know, the internal structure of a black hole. So therefore as far as we're concerned they have no internal structure My apologies Ken, no offence but that's a complete non sequitur to my way of thinking. If we don't know, we don't know. $\endgroup$
    – user108787
    Commented Sep 9, 2016 at 21:59
  • $\begingroup$ @CountTo10 Although I agree your comment, I think maybe a "we don't know" could be an acceptable answer here. $\endgroup$
    – peterh
    Commented Sep 9, 2016 at 22:02
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    $\begingroup$ @peterh yes, I totally agree. $\endgroup$
    – user108787
    Commented Sep 9, 2016 at 22:06
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    $\begingroup$ I'm playing through a logical definition here. An elementary particle has no (known) internal structure. Naturally we think of these things as incredibly small - the electron being a nice example. But a black hole has no (known) internal structure and can be miles across. So it's simply a big elementary particle? Like an elementary particle, it's a volume of pace-time to which we have no informational access. $\endgroup$
    – Ken Abbott
    Commented Sep 10, 2016 at 0:25

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I think your premise is quite an interesting one, and one that I have a bit of a sweet spot for in my own heart. The basic idea, as you said, is that elementary particles share a property with singularities in that they have no internal structure. Most of the physics I know along these lines has come from the opposing perspective however, rather than "can we explain black holes with particle physics," it's been "can we explain particles as black holes."

If I am recalling my history correctly, some early papers from Einstein himself tried to construct classical physics as just the theory of spacetime with holes, vorticies, much like black holes. John Wheeler also did interesting work along these lines.

The fundamental idea (turning yours on it's head) that perhaps elementary particles are quite similar to black holes is not very new. Wheeler's attempt at fleshing out these ideas essentially ended up becoming absorbed under the umbrella of Geometrodynamics, and the quantum theory thereof.

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    $\begingroup$ There is also apparently some realization of this in string theory, cf the references in physics.stackexchange.com/questions/264979/… (also: Greetings from UCSD! This is David - was an undergrad in mcgreevy's 217, you also TA'd a class I was in but I forget which) $\endgroup$
    – user12029
    Commented Sep 10, 2016 at 2:41
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    $\begingroup$ Hi David! Nice to see you out in the wild, small world! $\endgroup$ Commented Sep 10, 2016 at 16:14
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No, not possible. They just don't come, nor are observed, with unique values of mass or spin, or any of the quantum numbers that are associated with elementary particles.

Elementary particles come in very specific quantum numbers, for spin, parity, and others. They also have, for each elementary particle type (e.g., electrons, down quark, Higgs boson, etc) their unique masses. And they are indistinguishable from another particle of their type.

ADDED EDIT (this paragraph) As @Holger Fiedler points out in his comment, that it's a little different for photons - my take on what he may mean is that since they have zero mass photons of different energies have different effects, though still in all cases they follow exactly the same laws, just their interactions are energy dependent. Of course, all particles interact differently at different energies, also following their same laws, but they can always be brought to rest (in some reference frame) and then any measurements on them give the identical results. Still, a 'small' difference for photons because of their zero mass. It does not seem to me to affect the argument of this answer.

Black Holes (BHs) come in a seemingly continuous values of mass, and spin. All the measured BHs have their mass determined, more or less, by how much mass-energy has gone into making them. There are BHs that have been observed and whose mass and in some cases spin has been determined (approximately), and there is no multiples of a given mass, there is no discreetness. Moreover, when they radiate gravitational waves they loose mass, usually in much smaller quantities than the masses of other BHs.

You might be able to argue that they are composed of many elementary particles, and be consistent with these observed features, but that does not help your case. Even if it were so, they would be composed of many elementary particles, sort of like a nucleus has a bunch of protons and neutrons, or a proton a number of quarks and a large number of gluons. But saying they are composed of many particles is quite different from what you are saying. Mainly since once any particle becomes part of a BH, we stop seeing any quality/property of that particle. Only the total mass and spin (and charge if they have any) is observable from a BH - due to the No Hair Theorem.

String Theory has a better hypothesis, that it is composed of strings, and using that they can reproduce the entropy of a BH. There is also the AdS/CFT conjecture that says it is the strings inside that are represented at the horizon by a Conformal Quantum Field Theory. But there's too many unknowns to know if any of that is true.

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    $\begingroup$ Bob, your statement "And they are indistinguishable from another particle of their type" seems to me not holdable for photons. $\endgroup$ Commented Sep 10, 2016 at 6:16
  • $\begingroup$ @Fiedler. If you mean because different energies have different freqs and properties, you are right. We can't bring them to a stop so they could all look the same. Didn't think of that as I was writing. I'll change the post. Thank you. $\endgroup$
    – Bob Bee
    Commented Sep 10, 2016 at 17:31
  • $\begingroup$ Since BH has an entropy, it does not seem to be an elementary particle. Instead, it can be regarded as a huge exited string. As far as I can remember, there is a correspondence between a BH and an ecxited string according to L. Susskind. $\endgroup$
    – XXDD
    Commented Sep 12, 2016 at 4:05
  • $\begingroup$ I've seen something but it wasn't that simple $\endgroup$
    – Bob Bee
    Commented Sep 12, 2016 at 18:46
  • $\begingroup$ The fact that astrophysical BHs vary, much more than any type of particle that's observed (by us) as subatomic, would be consistent with the possibility that we're in a causally-separated (i.e., local) universe whose particles originated in their separation from antiparticles with which they had previously been paired, during the violent tidal effects of the gravitational collapse of a rotating star, with their trajectories accelerated and reversed by their contact with the spin of vastly larger stellar fermions. Nikodem J. Poplawski's elaborated on this cosmology in papers visible on Arxiv. $\endgroup$
    – Edouard
    Commented Mar 14, 2020 at 19:56

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