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Earth Science

Black Holes From the LHC Could Last For Minutes 672

Posted by kdawson
from the becoming-greyer dept.
KentuckyFC writes "There is absolutely, positively, definitely no chance of the LHC destroying the planet (or this way either) when it eventually switches on some time later this year. And yet a few niggling doubts are persuading some scientists to run through their figures again. One potential method of destruction is that the LHC will create tiny black holes that could swallow everything in their path, including the planet. Various scientists have said this will not happen because the black holes would decay before they could do any damage. But physicists who have re-run the calculations now say that the mini black holes produced by the LHC could last for seconds, possibly minutes. Of course, the real question is whether they decay faster than they can grow. The new calculations suggest that the decay mechanism should win over and that the catastrophic growth of a black hole from the LHC 'does not seem possible' (abstract). But shouldn't we require better assurance than that?"
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Black Holes From the LHC Could Last For Minutes

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  • by Jeremiah Cornelius (137) on Friday January 23, 2009 @11:09AM (#26575377) Homepage Journal

    ...Or "Knowing Enough to Be Dangerous".

    Stay tuned, as Rocky and Bullwinkle court certain doom!

  • Re:Well, duh! (Score:5, Interesting)

    by Mindwarp (15738) on Friday January 23, 2009 @11:22AM (#26575581) Homepage Journal
    Heh - when you're talking about a black hole at or smaller than the size of an atomic nucleus it doesn't matter whether it's at the top of the atmosphere or at the center of the Earth. Matter at that scale is described as tenuous at best. You'd have to get somewhere like the center of the sun or denser before a collision would be anywhere near likely.
  • Re:cosmic rays (Score:5, Interesting)

    by secPM_MS (1081961) on Friday January 23, 2009 @11:26AM (#26575655)
    Small black holes are far less dangerous than made out to be. I wouldn't like to be very near one due to its Hawking radiation (virtual photon creation near the event horizon where one of the virtual photons is absorbed and the other turns real as it escapes), but the fear mongers of black holes forget the limiting factor. Matter falling into a black hole is compressed and gets hot. The hot matter radiates light / gamma rays. While in some cases this radiation might be captured as well, it is far more likely that the radiation pressure will limit the rate of matter absorption by the black hole. The radiation pressure effect is known as the Eddinton effect and is a major factor in stellar stability. In the case of a small black hole, the size of the black hole is far smaller than the absorption length of gamma rays, preventing advection of the gammas. Since a non-rotating black hole is likely to convert on the order of 1% of the absorbed mass into gamma radiation, such a source would be more than capable of creating a near vacuum of hot matter about itself.

    If such stable black holes were creatable / existed, we should see rather remarkable things with old white dwarfs and neutron stars, which would be greatly affected by such energy sources.

  • Re:cosmic rays (Score:5, Interesting)

    by John Hasler (414242) on Friday January 23, 2009 @11:35AM (#26575817) Homepage

    > What happens if one of these black holes happens to intercept a spacecraft as it leaves
    > or re-enters the atmosphere? Does it do significant damage?

    No. Try to understand how small these holes would be. They are so tiny that in the unlikely event that they hit the nucleus of an atom they would almost certainly pass through with out interacting at all with any of the subatomic particles there. Your spacecraft is going to be hit by cosmic rays with far more energy and with a far higher probability of interacting.

  • Re:Bogus (Score:2, Interesting)

    by LWATCDR (28044) on Friday January 23, 2009 @11:43AM (#26575979) Homepage Journal

    Not at anywhere near this energy.

  • by MoonBuggy (611105) on Friday January 23, 2009 @11:48AM (#26576065) Journal

    I think that pretty much sums up the way that the scientists on these kind of projects really think about these things, and I find it reassuring. They are just as unenthusiastic about the prospect disappearing into nothingness as you are. They are smarter than me. They are also almost certainly smarter than you. If they are comfortable enough to joke/make bets then I'm not worried.

  • Re:Bogus (Score:5, Interesting)

    by blueg3 (192743) on Friday January 23, 2009 @11:48AM (#26576073)

    Actually, cosmic rays, which regularly (read: constantly) enter our atmosphere, have energies up to 10^20 eV. The LHC uses 7 TeV protons and ~500 TeV lead nuclei. That's on the order of 10^12 to 10^14 eV.

    So, you have it backwards. We don't produce particle at anywhere near the energy they're produced in nature.

  • Re:cosmic rays (Score:5, Interesting)

    by davolfman (1245316) on Friday January 23, 2009 @11:48AM (#26576075)
    What I find more interesting is that if these miniature black holes can give off a minute of Hawking radiation then it means the final seconds of a black hole look less like a bomb and more like a really bright flashbulb. This is great news for some science fiction authors as it means potential Hawking radiation reactors are actually NOT suicidal for a species to build.
  • by ball-lightning (594495) <spi131313@yahoo.com> on Friday January 23, 2009 @11:54AM (#26576233)
    Actually, a black hole at mars orbit wouldn't do any damage (to us) because if it swallowed up Mars, it would have the same mass as mars, thus leaving everything else untouched. A black hole on earth would well, not be enjoyable for us.
  • by AndersOSU (873247) on Friday January 23, 2009 @11:58AM (#26576335)

    I'm aware of the tongue and cheek nature of this post, but I'm also not a theoretical physicist, so can someone tell me if the current body of knowledge indicates any way to contain a black hole? In other words, it's impossible to put a charge on a black hole, right?

  • by hitmark (640295) on Friday January 23, 2009 @12:04PM (#26576465) Journal

    was there not some calculations done at the time that suggested that the atmosphere itself could be ignited?

  • by Junior J. Junior III (192702) on Friday January 23, 2009 @12:08PM (#26576523) Homepage

    But, see here's the thing: the black hole may have very little mass, and therefore attract very little nearby matter.

    However, it is also affected by the Earth's gravity.

    The black hole will fall downward, like all objects that have mass, drawntoward the center of the earth.

    Every bit of matter between the black hole and the center of the earth will fall into the black hole, adding to its mass like a snowball rolling down a hill.

    When the black hole hits the bottom of Earth's gravity well, the pressure of all the material above it will press downard into it, putting more and more Earth material past the black hole's event horizon. With nothing to stop the inward falling mass of the planet's mass into the hole, the hole will swallow the entire planet.

    The only way this won't happen is if the hole "evaporates" due to Hawking radiation more quickly than it can accrete mass, and loses sufficient mass such that it stops having an event horizon, eg ceases to be a black hole.

    Fortunately, calculations predict that very light holes would lose mass due to Hawking radiation very quickly. However, those calculations are apparently not as precisely calibrated as previously thought.

  • by wITTus (856003) on Friday January 23, 2009 @12:22PM (#26576781) Homepage
    Can't they first wait until humanity advances a bit further into space?
  • by clonan (64380) on Friday January 23, 2009 @12:31PM (#26576965)

    Charge is maintained. You can't destroy a negative without also destroying an equal positive.

    Therefore if you shoot a lot of electrons into the black hole it will develop a charge and the charge can be manipulated.

    After it has a charge you just need to shoot equal positive and negative charges

  • by medelliadegray (705137) on Friday January 23, 2009 @12:48PM (#26577301)

    If there is no time limit to these side odds of Enrico Fermi's--then odds could very well happen if we saw a WW3.

    I suppose it'd be pretty hard for man to technically wipe out all life with current technology. However, all of man and most large critters is close enough in my book. Hell, even knocking man back to the stone age is enough in my book.

    I wonder--did anyone bet on that one and side with annihilation? what were the odds he gave? :)

  • by gillbates (106458) on Friday January 23, 2009 @01:08PM (#26577717) Homepage Journal

    As a physicist, this whole thing has been an embarrassing reminder of just how bad physicists are at public relations...

    Take heart, your peers in climatology and meteorology haven't been able to convince the US that global warming is real, in spite of the fact that several key politicians picked up the cause.

    If being unable to convince people that a black hole *won't* happen is the worst you've done, count your blessings.

  • by hasdikarlsam (414514) on Friday January 23, 2009 @01:15PM (#26577837)

    No, actually, the black hole is so very minuscule (10^-27 meters) that it could fall straight through a nucleus without absorbing anything.

    For comparison, a proton is ~10^-16 meters. Or was that a quark? I'm not off by more than two or three orders of magnitude, anyway, which scarcely matters for this.

  • by manicfish (1192473) on Friday January 23, 2009 @01:33PM (#26578155)
    Except that (and this has been repeated time and time again above) -- it will NOT devour 'every bit of matter between the black hole and the center of the earth'. The chances of it hitting anything, even if it passes through the nucleus of an atom (which, relative to the size of the black hole, is largely empty space), is minuscule. The black hole would be so tiny, and its gravitational pull so slight, that the chances of it sweeping up any matter at all (let alone the entire planet) before it evaporated are not even worth bothering with.
  • Re:cosmic rays (Score:3, Interesting)

    by Goldsmith (561202) on Friday January 23, 2009 @01:56PM (#26578559)

    I wish the government shared your point of view! As a scientist, I'm not entitled to a lab, or funding, or students. I have to ask the government for the ability to do research and their permission to do the research I'd like to do (they regularly check on what I'm doing). If there's no government agency (or private company) that wants to fund me to do what I'd like, I have to do what they want me to do to pay the bills. Occasionally, you can slip some research in that's not supported, but you're not going to get something like the LHC without the government wanting it to happen.

    The question of funding the LHC is not quite the same. If we didn't fund the LHC, that money may or may not be invested in other areas of science. Even though it's a lot of money for one scientific project, it's a small amount to the collected governments which fund it. The highly educated people working on the LHC would have to be doing something else, and comprise a not insignificant section of the physics workforce.

  • by raduf (307723) on Friday January 23, 2009 @04:17PM (#26580991)

    AFAIK, Hawking radiation has a very very small rate of loss, a lot less then, for example, light reflected off the moon. If it wasn't so we could see black holes.

  • Re:Bogus (Score:3, Interesting)

    by budgenator (254554) on Friday January 23, 2009 @05:08PM (#26581805) Journal

    Not to mention the any blackhole produced will be traveling at the speed of light minus a smidgen and have a mass just a smidgen above zero, so when it's 1 second lifetime expires it'll be halfway to the moon's orbit anyways! Those blackholets will be traveling about 3.5 million times the Earth's escape velocity.

  • by HiThere (15173) <`charleshixsn' `at' `earthlink.net'> on Friday January 23, 2009 @10:28PM (#26585013)

    Actually, it wouldn't be *THAT* difficult to wipe out all life on Earth, if that was your intention, and you controlled a major country (or equivalent) and you could afford to be patient. Asteroid orbits aren't *THAT* difficult to perturb. You might have to make a few orbital corrections, but I think that a solar powered mass driver on a large asteroid could probably perturb the orbit in a way that would wipe out all life on Earth within a century...though possibly some of the bacteria that live deep underground would survive.

    The thing is, nobody with a lot of power has a goal of wiping out all life on Earth. If they did, who would remember their name and deeds later? It's not that nobody goes crazy that way, but it's a quite unusual craziness, and it's an unusual situation where such a person can maintain power for a long time. Besides, it's so much easier to just kill off all the people. There are probably 7 countries that could do that without any further investment, and without requiring enough patience to wait for a century (or at least decades...I haven't run the calculations).

  • Re:It's Crazy (Score:3, Interesting)

    by aliquis (678370) <dospam@gmail.com> on Friday January 23, 2009 @10:29PM (#26585023) Homepage

    And you're willing to probe that general area?

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