Talk:Micro black hole

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Contents 1 This Article Needs Translation 2 Electron black hole 3 Request for order-of-magnitude estimates 4 Re-cast 5 Black hole analogies 6 Article on the lack of radiation from orbiting electron?

[edit] This Article Needs Translation

This article needs to explain it's main points so that non-scientists may follow it's essence.

It fails to explain it's key terms in everyday language-- for example what is a Plank mass or a Hawking measure and why are they significant to the discussion of micro-black holes?

As it stands, this is an insular piece written for physics insiders.

Good science writing for public consumption will speak clearly to both the scientist and the lay person--

And especially given the nature of Wikipedia as a public informtaion source-- translation and clarification are needed here.

Sean7phil 23:19, 22 May 2007 (UTC)

[edit] Electron black hole

We ought to get rid of this sentence: "It has been suggested that the electron may be a micro black hole, for more info see the discussion here." It's self-referential: a Wikipedia article shouldn't refer readers to an editorial discussion held about another Wikipedia article in order to back up a theory. I haven't taken it out because someone who knows what they're talking about can hopefully rephrase it to explain how exactly an electron might be a micro black hole, and who has suggested this. I must say it's the first I've heard of it, but then I'm no physicist. — Trilobite (Talk) 17:25, 7 Mar 2005 (UTC)

There was a short paragraph concerning the possibility of an electron being a black hole, however, I felt the text was redundant and there should simply be a link to a more thorough discussion of the topic. I agree that the sentence should be taken out, but should I then just re-enter the random paragraph, take it out entirely, or create a complete and official section on the possibility? Feel free to change it yourself if you think you know what to do. (in the mean time I will replace the sentence with the original paragraph. rmrfstar (Talk) 02:41, 8 Mar 2005 (UTC)

Thanks. Reintroducing the paragraph seems like the best option for now. I don't know what to do about this unfortunately - it is not my area of expertise at all. I do feel however that we need to lose the self-reference. If anyone comes to this talk page wondering about that para the link is here for them: Talk:Electron#Is the electron a small black hole?. — Trilobite (Talk) 04:07, 8 Mar 2005 (UTC)

I added the paragraph concerning the electron being a black hole because it seemed interesting and informative. If this is not appropriate please delete it. User:DonJStevens

The electron spin may explain its stability. Black hole theory predicts that a rotating black hole with maximal spin will not have the elevated temperature needed to emit Hawking radiation. See book "Hidden Unity In Nature's Laws" by John C. Taylor, pages 370 and 371.--- DonJStevens 14:47, 7 December 2005 (UTC)

I found this to be an absolutely fascinating exposition so I wikified it and turned it into a full-fledged article at electron black hole. linas 05:39, 4 Jun 2005 (UTC)

[edit] Request for order-of-magnitude estimates

Can someone add numerical estimates for following: what is the Hawking decay time for a 511KeV micro black hole? a 1 GeV micro? A 1500 TeV micro black hole (the last would be creatable by LHC colliding lead nuclei.)

If Hawking radiation was "wrong", i.e. didn't exist, so we dealt with a classical black hole that doesn't decay, how long would it take a 1500TeV classical black hole to "eat" some significant chunk of mass? For example, say I plunked the a (neutrally charged) 1500TeV black hole half-an-angstrom from a hydrogen atom. How long before it ate the electron? the proton? (Clearly a charged black hole would eat "instantly" until it became neutral, and then slow way down). How long would it take to eat a gram of material (avogadro'snumber worth of hydrogen atoms) How about a few thousand tonns (at which point it becomes gravitiationally significant)? Just curious, and of course you know why :) linas 05:51, 4 Jun 2005 (UTC)

well, you could probably get a rough estimate based on newton's universal gravitation. I don't know exactly how accurate this would be compared to an all out GR calculation. Cpl.Luke 9 July 2005 05:28 (UTC)

The evaporation time is derived at Hawking radiation. Subbing in constants, it works out to:

Where M₀ is in kg. 1 eV is about 1.78e-36 kg, So decay times are:

• 511 keV (electron mass): 6.3e-107 s
• 1 GeV (proton mass): 4.7e-97 s
• 1.5 PeV (RHIC total energy): 1.6e-78 s

All of these are far shorter than the planck time, and the temperatures of the black holes would be much higher than the planck temperature, making these results unphysical (read: "really suspicious"). In practice, this reflects the fact that objects that small can't be black holes if our understanding of physics is correct (the smallest black hole is roughly the planck mass, unless extra dimensions or the like skew things). --Christopher Thomas 9 July 2005 15:08 (UTC)

As for "time required to eat things", to get numbers for that, you calculate the interaction cross-section between the black hole and protons/neutrons, and then plug in the density of whatever matter you assume it's orbiting in. I'll grind out numbers on Monday. I expect it to give a result that's very sensitive to the mass of the black hole. Also, for black holes smaller than the radius of a proton (pretty much all of these examples), the actual interaction mechanism will be absorption of a single quark. The result will be a black hole that carries color charge, which is bound into the nucleon it interacted with until it eats the other quarks. Cross-section for this depends on the wavefunctions of the bound quarks, which is a bit iffy (quark masses and nucleon binding energies aren't precisely known). Alternatively, if the black hole is moving very quickly, it might fail to drag the remaining quarks with it, which gives you a quark/antiquark pair forming when the bonds between the hole and the remaining quarks break. This is important because it affects how quickly the black hole slows down in matter (energy for pair production is sapped from the hole's kinetic energy). Speed threshold for a hole lighter than the nucleon is when the hole's kinetic energy exceeds pair production energy, and for the case where the hole is much heavier, it's where the energy required to accelerate the remaining quarks to the hole's speed is greater than the pair production energy. This is at least a really nifty problem, even if it isn't likely to happen much in the real world. --Christopher Thomas 00:56, 10 July 2005 (UTC)

Wow, thanks! Care to summarize some portion of this, and place it in the article directly? This is to serve several purposes: first is that I gather that there are conflicting definitions of what constitues "micro": by some, its stuff in the million-kilogram range, not the GeV range. The other aspect has been lay-peoples concerns on hearing that RHIC may produce black holes; an at least partly-informed discussion along the lines you give would be suitable for this article. linas 01:39, 10 July 2005 (UTC)

I'll do what I can during the week. The definition I'd heard was along the lines of "sizes at which quantum effects become significant", which would be anything approaching the Planck mass (from above). However, I have no idea what definitions are accepted as authoritative (could even be a catch-all for "anything sub-stellar"). As for RHIC black holes, I'll do what I can to outline the arguments both ways (this seems to come up every time there's a new particle accelerator). For now, I'm going to sleep :). --Christopher Thomas 06:58, 10 July 2005 (UTC)

We use to think the proton was about 1700 times smaller than an electron, but about 1700 times heavier, thus making the density about 3 million times greater. Electrons and protons are much too small to view with a microscope, but we have had some recent success imaging larger molecules which are thousands to millions of times bigger than electrons. Plank length is much smaller than an electron or proton and plank temperature is much hotter than the center of the hottest stars which are trillions of degrees in r,k,c or f = rankine, kalvin, celcius or farenheit. Modern writters seem reluctant to give us numbers.Ccpoodle 08:59, 6 July 2007 (UTC)

[edit] Re-cast

I've been bold and changed the article around quite a bit, to try to play up much more and much sooner why the Planck mass for a black hole is so important -- basically this is the mass below which we would expect Hawking radiation to be suppressed, and the gravitational entropy to get really granular.

That was my aim, anyway; which I hope was sensible.

(Note also that if the "Black hole" (if that is what it still is) becomes rather limited (quantised) in how it can emit particles, it probably also becomes similarly limited in how it can absorb them -- ie very very unlike a classical black hole).

But I'm not sure how well what I've written reads. For one thing, I've now made it too long as a single lump of text without subdivision. For another, I suspect that too many of my sentences are too ungainly, so the whole thing could do with simplifying, spring-cleaning and freshening.

I also may have now too much downplayed (basically reflecting my ignorance) the discussion of what "quantum" black holes with mass less than M_P might be like - which was the original focus of the article.

I hope people will think that anyway what I have done is still on balance an improvement. But I suspect the article could now definitely benefit from a good reactive sorting-out edit from other eyes and other hands. Jheald 13:15, 21 July 2006 (UTC).

[edit] Black hole analogies

Black hole analogies, are merely that -- analogies of black holes. They are not micro black holes with a new name. They do not belong in this article. For more information see User_talk:Quasarq. McKay 04:15, 14 September 2006 (UTC)

[edit] Article on the lack of radiation from orbiting electron?

"...an electron constantly accelerating round an atom does not radiate, despite the apparent predictions of classical electrodynamics."

Is there an article anywhere which details this phenomena (or lack of)? - Inquiring minds wish to know. --Ceriel Nosforit 07:25, 16 May 2007 (UTC) Mainstream resently has decided electrons don't orbit, they vibrate. If they orbit at accelerating speeds they would approch the speed of light and approach infinate mass relative to an ouside observer. Ccpoodle 09:12, 6 July 2007 (UTC) Or are they just a combination of strings.... —Preceding unsigned comment added by 82.217.115.116 (talk) 22:29, 7 April 2008 (UTC)