Tuesday, July 1, 2008

LHC again

I am amused at all of this. It is most interesting that "fear and trembling" is based on theoretical physics. How can the absence of empirical data influence a sound system of knowledge. As I mentioned earlier...Y2K or fall off the edge of the Earth--redux.

The latest...

"Planet Survival, Pro and ConWill the earth be obliterated by Labor Day?"

What the Times didn't tell you


Timothy Noah

June 27th, 2008


The New York Times keeps reporting that there may be an itty-bitty chance that when the Large Hadron Collider at the European Center for Nuclear Research (CERN), located just outside Geneva, Switzerland, gets switched on late in August, the world will come to an end. But probably there is no such chance, even an itty-bitty one.

A story like this poses difficult questions about news placement.

If there's even a microscopic chance that human agency will destroy the planet—the CERN accelerator is the world's largest—then surely this news belongs on Page One. That's how the Times played it on March 29 with Dennis Overbye's story, "Asking A Judge To Save the World, and Maybe A Whole Lot More."

On the other hand, news stories announcing even a microscopic chance that human agency will destroy the planet risk creating worldwide panic. After all, as my friend Gregg Easterbrook pointed out in a fine cover piece in the June Atlantic ("The Sky Is Falling"), it's much likelier that humankind will be wiped out by an asteroid. In the piece, Easterbrook reported that an asteroid specialist for the Air Force put the likelihood of a "dangerous space-object" collision in any given century at one in 10. (Caveat: Not all such collision scenarios, which include comets and meteors in addition to asteroids, posit the destruction of all human life on the planet.)

The Times has kept follow-ups to the end-of-the-world story off Page One. Overbye published an explanatory essay in the paper's science section on April 15, and on June 21 he published deep inside the Times A section a news story bearing the whimsical headline, "Earth Will Survive After All, Physicists Say." On June 27, Overbye reported, again inside the Times A section, that the United States was seeking to dismiss a lawsuit by two worried citizens aimed at preventing anyone from throwing the big switch at the Large Hadron Collider. The government's principal response, I'm sorry to report, wasn't that there's no chance that switching on the Large Hadron Collider will bring about the end of the world, but rather that a six-year statute of limitations has already passed.

I can well understand why the Times doesn't want to give sustained big play to the possibility that the world will end on or around Labor Day. In addition to the civic-minded concern that this might create worldwide panic, there are practical matters of self-interest. If the possibility weren't realized, as most scientists seem to expect, then the Times would look foolish. If the possibility were realized, it would have no opportunity to collect a Pulitzer, because the Times, the Pulitzer board, the Columbia University Graduate School of Journalism, which gives out the award, and every last Times reader would all be obliterated, along with the rest of the planet.

On the other hand, when readers are invited to ponder the possibility, or lack thereof, that the Large Hadron Collider will obliterate their planet—even when that invitation is extended in an edgy Timesian spirit of good fun—they deserve a decent summary of the arguments pro and con. Overbye has done a very poor job in this regard. I don't know one-tenth about this subject as Overbye, but since he let you down, your faithful Chatterbox is duty bound to step into the breach. (A previous Slate "Explainer" column on this topic focused, like the feds, on legal issues at the expense of scientific ones.)

To keep things simple, I will limit discussion to the possibility that the Large Hadron Collider will swallow up the planet in a black hole. This is the most-discussed doomsday scenario. (I should note in passing, however, the existence also of scenarios involving "strangelets," a hypothetical category of matter that might set off an uncontrollable fusion chain reaction that would transform the planet into what the BBC calls a "hot, dead lump"; "magnetic monopoles," a hypothetical thingamabob that might conceivably destroy protons, hence atoms, hence matter, hence Planet Earth; and vacuum bubbles, which might alter the entire universe in some way that would render humankind extinct.)

Both sides in the black-hole version of the doomsday argument recognize that the Large Hadron Collider may create black holes. These would be little ("microscopic") black holes. The majority view, as articulated by CERN scientists, is that microscopic black holes are harmless, that cosmic rays create them all the time, and that they traverse our planet at very near the speed of light on a regular basis without causing so much as a nosebleed. The minority view, as articulated in an affidavit filed in federal court by Walter L. Wagner, a retired federal nuclear safety officer, might be summarized by quoting Bruce Springsteen: "From small things, mama/ Big things one day come." According to this view, CERN-created microscopic black holes would be different because they would travel more slowly, increasing the possibility that they would be captured by the earth's gravity, enabling them to gobble up matter and grow bigger, like the monster plant Audrey II ("Feed me") in Little Shop of Horrors, until eventually they gobbled up Planet Earth itself.

Brian Cox, a University of Manchester physicist who works on the Large Hadron Collider, responded to the doomsday argument in an interview posted June 26 by O'Reilly Media. I will give him the last word:

You read on the web, well, what happens if these black holes fly straight through the planet before they have a chance to eat it? Whereas the one that the LHC could [create would] just sit there and perhaps sink to the center of the earth? It turns out that when you do the calculation the black holes are so small that even if they didn't decay and they just sat there they wouldn't come close enough to any matter—because matter is basically empty space—to dissolve and to [inaudible] the matter and to grow so they wouldn't do any damage. Okay; why don't you ignore that? Well the final piece of wonderful evidence which confines these idiots to the bin is that you look up into the sky and you see white walls—some neutron stars—very, very dense stars. Cosmic rays are hitting those with energy greater than those seen at the LHC so if you can make black holes, black holes will be created on that surface. It turns out that they're nuclear dense, these stars, so the black holes are not going to fly through there; they're going to sit there and they're going to eat away and they're going to eat away much quicker than they could eat away the earth because the matter is much denser. So people have calculated how many neutron stars or white walls you would see in the sky if this were happening. If they were getting eaten by little mini-black holes and it turns out that there'd be very few indeed—in fact probably pretty much none, and you can do the calculation. So there's a whole layer [laughs] that—I don't need to reassure you anymore, I'm sure, but there are layer after layer after layer of—of tests and some of them are observational and some of them are theoretical and it turns out that it's utter nonsense.

I won't pretend to understand very much of this. But it does seem reassuring.

And from Scientific American:

"As LHC Draws Nigh, Nobelists Outline Dreams--And Nightmares"


JR Minkel

July 2nd, 2008

Scientific American

The number 14 turns up conspicuously in discussions of the Large Hadron Collider (LHC), the soon-to-be world's biggest particle accelerator. Construction of its underground, 17-mile (27-kilometer) ring on a site near Geneva, Switzerland, has taken 14 years. It is designed to reach energies of 14 tera- (trillion) electron volts (TeV), or about seven times that of the Tevatron, the world's currently reigning accelerator at Fermi National Accelerator Laboratory in Illinois.

And project leaders at the European Organization for Nuclear Research (CERN) announced today that next month workers should be done chilling the machine's 50,000 tons of magnets to temperatures colder than deep space—a bracing –456.3 degrees Fahrenheit (1.9 kelvins)—making them ready to whip opposing beams of protons to near light speed and collide them so researchers can pick over the debris.

The expected cool-down date? The week of July 14.

Needless to say, switching on the largest, most complex science experiment ever constructed will be a drawn-out process. "There's no red button to press," James Gillies, a CERN spokesperson, said during a news conference yesterday Web cast from the CERN Control Center in Prévessin, France. The lab plans to send the first protons through the ring in mid-August, then spend a couple of months ramping them up to high energies. Ideally, the LHC's massive particle detectors should be ready for action at around the same time.

In anticipation of the start-up, CERN convened a panel of five Nobel Prize–winning physicists to give their thoughts on the project. The LHC was built first and foremost to seek out a subatomic particle called the Higgs boson, which solves the conundrum of why the photon (the particle that conveys the force of electromagnetism) has no mass, whereas its counterparts, the W and Z bosons (the operative particles in the weak nuclear force that causes radioactive decay), do.

Physicists believe that the Higgs breaks a symmetry between these forces, similar to the way Earth's gravity makes it appear that space has an up and a down. It does so by acting like molasses that other particles have to plow through. The end result is mass as we know it.

Most of the panelists said they were confident that the LHC would uncover the Higgs, because its presence (or at least something like it) is so strongly implied by the standard model of particle physics, which describes the three forces that hold atoms together. (In addition to electromagnetism and the weak force is the strong nuclear force that keeps individual protons and neutrons from dissolving into more basic particles called quarks.)

Discovering the Higgs would close a three-decade-long chapter in the history of physics. "We are all enormously excited that the LHC is about to turn on," said David Gross of the University of California, Santa Barbara, co-winner of a 2004 Nobel for elucidating the strong nuclear force.

Part of the enthusiasm stems from the fact that the standard model was so successful that physicists have no firm clues on how to proceed beyond it. Even more interesting than the Higgs, panel members said, would be the discovery of particles responsible for dark matter as well as an explanation of why the universe has a preponderance of matter over antimatter, either of which would break new ground in fundamental physics.

And then there's the far-out stuff: George Smoot of the University of California, Berkeley, who shared the 2006 Nobel Prize in Physics for mapping the faint cosmic microwave background radiation that gave evidence of the big bang, mentioned the prospect of finding signs of extra dimensions of space implied by string theory. "I have really high hopes‚ Äîperhaps too high," he said.

Gross, who described himself as more conservative, said he expected the LHC to reveal supersymmetry, a proposed theory in which each particle has a heavier counterpart; such a discovery could explain the existence of dark matter as well as solve some lingering coincidences in particle physics known as unification and the hierarchy problem, which have to do with why the forces appear so different from one another.

Of course, nature might throw researchers a curveball. Martinus Veltman of the University of Michigan at Ann Arbor (Nobelist in 1999 with Gerard 't Hooft of Utrecht University in the Netherlands for work on the weak force that paved the way for the Higgs) suggested a gloomy but speculative scenario in which Higgs exists but fails to show up at the LHC. If that happens, he predicted, "it will probably be the end of particle physics."

Gross said that such a result, going against the standard model, would itself be "enormously exciting." What worried him was finding the Higgs and nothing else, because then it would be impossible to persuade world governments to fund future machines such as the proposed International Linear Collider, which took a hit in December when Congress yanked 2008 funding for the U.S. share of R&D on the project.

Without some hints from nature, physicists would not even know how big to build their machines to try to make new discoveries, Gross said. "My nightmare is we find the Higgs and nothing else," he said. "I have a lot of confidence that we won't, but that is a nightmare."

't Hooft, the fifth panelist, who shared his prize with Veltman, said even if the LHC turned up nothing but the Higgs, physicists would still keep the machine busy studying the way it interacts with other particles. Prior particle accelerators were considered successes for doing essentially the same thing, he said.

The discussion touched at least one laureate's nerves. Theoreticians "have too much time to think" sometimes, Carlo Rubbia (awarded half the 1984 physics prize for experiments that led to the discovery of the W and Z bosons) charged. Rubbia, a former director general of CERN who is considered the father of the LHC for his early work on the project and now holds scientific advisory positions at several European institutions, asked if Veltman would return his share of the Nobel Prize money in the event the LHC found no sign of the Higgs. (Veltman replied that he had already spent it.)

Despite the excitement and sense of urgency, all of the Nobelists acknowledged that uncovering nature's secrets takes time. This, too, however, became a touchy subject. When asked how long before the LHC will perform its first experiments at full energy, Rubbia betrayed signs of exasperation, noting that glitches are to be expected. "This is not going to be a fault, this is not going to be a failure," he said, if there are unexpected delays. "The science community needs peace and tranquility to get over all these problems."

Gross noted that it would take at least several years before evidence of Higgs began to come in. An LHC timeline circulated in April at a physics meeting in St. Louis indicated that certain varieties of supersymmetry ought to show up even before the Higgs does.

The bottom line, Smoot said: "We're all looking for this to be a revolutionary situation, and no matter what comes out, it will tell us something."

Government and lawyers put suits to rest

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