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Jan 29, 2009 05:45 PM | 13
One corollary of the delayed start-up of the Large Hadron Collider (LHC), the world's largest particle accelerator, is that it gives physicists—and the rest of the world—more time to mull the much-discussed possibility that the LHC could produce Earth-gobbling black holes.
In a paper posted recently to arxiv.org, physicist Roberto Casadio of the University of Bologna in Italy and his co-authors argue against such a scenario. But the bulk of the attention following their analysis has focused on their observation that microscopic LHC black holes, should they arise, could persist for seconds before decaying. (To wit, Fox News's story headlined: "Scientists Not So Sure 'Doomsday Machine' Won't Destroy World.")
It's worth pointing out that these collider-induced black holes only arise in certain theoretical frameworks, which posit that we reside in a universe of more dimensions than the four (three for space, one for time) that we're used to. In fact, the Casadio team's analysis presumes a certain five-dimensional theoretical model of the universe known as the Randall-Sundrum (RS) model. Although the RS model has its adherents, many alternatives exist—in fact, it is hoped that the LHC will help illuminate which of the competing big-picture theories is correct (or at least more likely to be correct).
It's also worth pointing out that such concerns have been raised before. As noted in a 2007 New Yorker feature about the LHC, a similar argument was raised in 1999 around the start-up of Brookhaven National Laboratory's Relativistic Heavy Ion Collider (RHIC). The article points out that Scientific American played a role in the controversy by printing a letter asking whether a black hole at Brookhaven could devour the Earth in minutes, along with a reply from physicist Frank Wilczek, then of the Institute for Advanced Study in Princeton, N.J. In his response, Wilczek dismissed the black-hole scenario but mused that an alternate disaster might theoretically arise via the production of strangelets, a hypothesized form of matter. Although he cautioned that such a catastrophe was "not plausible," the media seized on the mention and Brookhaven was forced to convene a panel of physicists to vouch for the collider's safety. (The RHIC has been running since 2000.)
Even presuming we live in a universe in which the LHC is capable of producing black holes, and even presuming that the initial conditions are such that the miniature gobblers can survive for some seconds, Casadio and colleagues calculate that such black holes would be unable to grow to catastrophic size before decaying. But, like Wilczek's strangelet comment, the extended black-hole lifetimes hypothesized by Casadio and his co-authors are bringing collider safety concerns back to the fore.
PHOTO OF REPLACEMENT FOR DAMAGED LHC MAGNET © CERN
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particle physics,
particle accelerator,
doomsday,
Large Hadron Collider,
black hole machine,
Brookhaven,
atom smasher
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13 Comments
Add CommentCasadio, Fabi, and Harms assume that black holes will decay via Hawking radiation. It should be of additional concern that Hawking radiation has never been seen nor tested, and the fundamental theory behind Hawking radiation has been questioned in two recent peer-reviewed physics papers (cited below). If black holes are created and do not decay, we could have problems. Since this scenario is speculative it might be appropriate to assign it a moderately low subjective probability. However, standard expected value calculations (probability times cost) result in an enormous negative expected value when the cost at issue is the loss of Earth.
Reply | Report Abuse | Link to thisWilliam G. Unruh and Ralf Sch�tzhold, "On the Universality of the Hawking Effect," Physics Review D 71(2005) 024028.
Adam D. Helfer, "Do black holes radiate?" Reports on Progress in Physics. Vol. 66 No. 6 (2003) pp. 943-1008.
I highly doubt that the LHC will put us out of our misery. We are not that lucky LOL.
Reply | Report Abuse | Link to thisThe Earth isn't flat, either. But there are still folks out there who believe it. Personally, I can't wait for the LHC to really get down to work. My bet--no Higgs boson.
Reply | Report Abuse | Link to thisPhysicists seem to agree on disagreeing. Some say minute black holes may be induced by the LHC (albeit short-lived), others surmise that these may just be pure theoretical construct.
Reply | Report Abuse | Link to thisWhy take the risk for a plausibility of creating unwanted black holes? If the worry has been genuine, why not just shut down the monstrous yet mal-functioning LHC and re-channel whatever fund there is to some other more benefiting and down to earth researches?
Another sub-heading of this Sciam Daily Digest suggests, “Forget nuclear fission, how about fusion?” Indeed, how about spending more money on fusion research, as being done in UK for decades?
(Tan Boon Tee)
We are not going to destroy ourselves, I am not physicist, call it a hunch. I can't wait to see what happens when the LHC really gets going! And if it's the end of us, I assume it will happen pretty fast and we'll never know...
Reply | Report Abuse | Link to thisbiker-dude's life sucks, out of money, girl left me, have no friends, everybody hates me, just get it spinning and bring it on... I volunteer to be sucked in first...
Reply | Report Abuse | Link to thisbiker-dude's life sucks, out of money, girl left me, have no friends, everybody hates me, just get it spinning and bring it on... I volunteer to be sucked in first...
Reply | Report Abuse | Link to thisI must witness this event up close and in person, I must be the first too volunteer and go where no Person has gone before. cause I am a total Misanthropist. my saying is beam me up, scotty TAKE ME TAKE ME. PLEASE. I would like to volunteer to enter the chamber if I make it that far. I understand the magnetic force is extreme, in the LHC chamber.
Reply | Report Abuse | Link to thiseven if a black hole was created,(which is very unlikely) it would evaporate within fractions of a second
Reply | Report Abuse | Link to thiseven if a black hole was created,(which is very unlikely) it was be far too small to swallow earth and it would "evaporate" within a fraction of a second, a few seconds tops
Reply | Report Abuse | Link to thisAs mentioned in the news report, Casadio et al. concluded that any micro black holes produced by the LHC would be unable to grow "to castastrophic size." However, their conclusion has been challenged by a colleague whom they thanked in their acknowledgements.. In an appendix to a revised paper released on Aug. 9, 2009 at http://arxiv.org/abs/0808.1415v3 , physicist Rainer Plaga, Ph.D., points to a serious flaw in their argument. He concludes:
Reply | Report Abuse | Link to this"Casadio et al. correctly and usefully identify the range of a crucial theoretical parameter Mc for which black-hole growth is not catastrophic, but offer no argument of how to exclude that the Mc lies outside this range."
If you have photons travling at 99.9 % the speed of light, clockwise, and photons travling at 99.9% the speed of light ccw, what is their closing speed, what is their closing speed if you are sitting on one?
Reply | Report Abuse | Link to thisThis is all crazy talk. THEY are already doing this on stargate sg1. How will those guys get back? I'm gonna start building my bunker. Material suggestions?... Anyone?
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