Sensitive Dark Matter Detector Draws a Blank
An artist illustration showing the view from inside the Large Underground Xenon (LUX) dark matter detector buried deep below the Black Hills of South Dakota. Image released Oct. 30, 2013.
Did you own a toy race-car track as a child? Ever crash your model trains into one another just to see what happened? If you did, then congratulations, you already know some of the basic principles behind the Large Hadron Collider (LHC). Built by the European Organization for Nuclear Research (CERN), the 27-kilometer tunnel buried in the Swiss countryside exists to smash particle beams into each other at velocities approaching the speed of light. The idea is to use the resulting data to better understand the structure and origins of the universe. We're talking heavy questions and even heavier answers. Perhaps it's understandable that some critics, conspiracy theorists, crackpots and (alleged) time travelers might fear something more substantial than the Higgs boson particle. In this article, we'll run through some of the more popular misconceptions about the LHC and how little you have to fear about it causing the end of the world as we know it.
5. CERN Is Making an Antimatter Bomb
The Dan Brown detective novel (and movie adaptation) "Angels and Demons" centers on a plot to steal an antimatter bomb from CERN and blow up the Vatican with it. While the blockbuster delivered its share of action and intrigue, it fell short on facts. Two of the film's biggest mistakes revolved around antimatter's potential use as both an energy source and a weapon. Yes, when an antimatter particle comes in contact with normal matter, the two particles destroy each other and release energy. But CERN is quick to point out that the energy payoff simply isn't there. In fact, the transaction is so inefficient that scientists only get a tenth of a billionth of their invested energy back when an antimatter particle meets its matter counterpart. As for developing an antimatter bomb, the same principles apply. CERN points out that, at current production rates, it would take billions of years for the organization to produce enough antimatter to generate an explosion equal to an atomic blast.
4. Fun-sized Black Holes
Some concepts don't become tamer when you tack a "micro-" or a "mini-" prefix in front of them. For example, a mini-stroke is still an excellent reason to visit the hospital, and you'd certainly be ill advised to question the power of a minigun. So when CERN scientists mention that they might create microscopic black holes in the midst of their particle smashing, it's easy to understand some of the ensuing panic. Based on Einstein's theory of relativity, a few speculative theories lend a sheen of possibility to micro-black hole creation. The good news is that these theories also predict the micro-black holes would disintegrate immediately. If these black hole welterweights did hang around a little longer, it would take billions of years to consume the mass of a tiny grain of sand. That means no reducing the European countryside to a singularity and certainly no destroying the planet "Star Trek" style.
3. Attack of the Strangelets
Read enough space publications and your perception of the universe changes pretty fast. Once you get beyond the absurd vastness of the cosmos, you encounter such mind-rending notions as black holes, antimatter and dark matter. After you've swallowed the notion of a gigantic star collapsing into something smaller than a pinhead, it's easy to get bowled over by the idea of universe-destroying strangelets. Strange matter is presumed to be 10 million times denser than lead and was birthed during the Big Bang from the hearts of dense stars. The fear, which originated with the start-up of the Relativistic Heavy Ion Collider (RHIC) in 2000, is that the LHC will inadvertently produce strangelets -- tiny particles of strange matter -- and that these particles will swiftly convert surrounding normal matter into even more strange matter. It only takes a thousand-millionth of a second for the chain reaction to convert the entire planet. Strangelets, however, are purely speculative, and haven't surfaced in over eight years of RHIC operation. CERN says that the RHIC was far more likely to produce the theoretical matter than the LHC, so there's really no chance of it consuming the planet.
2. Time Travelers Hate It
In "Bill & Ted's Excellent Adventure," the titular slacker duo wields time travel with the logic of a 12-year-old. When Bill and Ted need a cell key to bust a few historical figures out of a modern California jail, they simply make a mental note for their future selves to travel back in time and plant the key where they can find it. While the 1989 buddy comedy is pretty much the antithesis of hard science fiction, its view of time-travel logic is shockingly similar to a 2009 theory regarding the LHC. Danish string theory pioneer Holger Bech Nielsen and Japanese physicist Masao Ninomiya, in a series of posted physics articles, laid out their theory that the Higgs boson particle is so abhorrent to nature that its future creation will send a ripple back through time to keep it from being made. Naturally, this theory summons images of T-800s, Jean-Claude Van Damme and Hermione Granger all galloping back through time to prevent future disasters, but not everyone is busy cracking jokes and reminiscing about time-travel movies. The two scientists aren't even talking about shadowy strangers from the future, but merely "something" looping back through the fourth dimension. Imagine a poorly designed bomb that, upon creation, destroys half the bomb factory. Now expand that example out from the confines of linear time.
1. Gateway to Hell
Black holes, antimatter explosions and even strangelets all originate from scientific fact and theory (albeit with a bit of imagination thrown in). Forget all that for the moment and consider the "Satan's Stargate" theory, proposed by Chris Constantine, better known on the Internet as YouTube user gorilla199. Constantine charges that the LHC exists "to disrupt a hole in the Van Allen belt that surrounds the Earth" and "to allow the return of the Annunaki from the planet Nibiru in order that they can come here, corrupt the rest of the Earth and do battle with God at Armageddon." There's also some stuff in there about freemasonry, cosmic rays and the Old Testament offspring of humans and fallen angels. According to BBC News, Constantine received a suspended sentence for DVD pirating after his defense attorney charged that Constantine suffered from a serious psychiatric condition. The Antichrist could not be reached for comment.
A new experiment buried deep underground has proven itself to be the most sensitive dark-matter detector ever built. But the first results from the high-tech instrument have turned up empty in its search for elusive dark matter, scientists announced today (Oct. 30).
Housed 1 mile (1.6 kilometers) underground in the Black Hills of South Dakota, the Large Underground Xenon (LUX) experiment's sensitivity makes it better at seeking out dark matter than any other detectors built for that purpose, LUX officials said. Although the powerful dark matter detector has just completed its first run, LUX has not yet found conclusive evidence of the elusive substance.
"The universe's mysterious dark sector presents us with two of the most thrilling challenges in all of physics," Saul Perlmutter, of the Lawrence Berkeley National Laboratory and a winner of the 2011 Nobel Prize in physics, said in a statement. "We call it the dark sector precisely because we don't know what accounts for most of the energy and mass in the universe. Dark energy is one challenge, and as for the other, the LUX experiment's first data now take the lead in the hunt for the dark-matter component of the dark sector." [Photos: Dark Matter Throughout The Universe]
Scientists think that dark matter makes up the majority of the matter in the universe; however, it cannot be seen or touched. Astronomers detect dark matter because they have seen its gravitational effects on galaxies and stars.
By running experiments like LUX far underground, scientists hope to shield the dark-matter detector from everything but WIMPs — weakly interacting massive particles that are thought to be the leading candidates for the particles that make up dark matter.
"LUX is the quietest place verified in the world," Rick Gaitskell, a Brown University physicist, said during a seminar on the findings. "That's how far we've had to go in order to be in a position to look for these WIMPs."
LUX is particularly adept at searching for low-mass WIMPs, which are predicted by some theoretical physics models. WIMPS are extremely difficult to find because they rarely interact with ordinary matter, except through gravity, LUX officials said.
Scientists think that WIMPs can be both low-mass and high-mass, and LUX has an enhanced sensitivity to low-mass WIMPs. The dark-matter detector recently completed its first data-collecting research run.
Through the course of the approximately three-month WIMP search, scientists did not find signals of WIMPs, although previous experiments with other detectors predicted that they would.
"Three candidate WIMP events recently reported in ultracold silicon detectors, however, would have produced more than 1,600 events in LUX's much larger detector, or one every 80 minutes in the recent run," LUX officials said in a statement. "No such signals were seen."
LUX houses a 6-foot-tall (1.8 meters) titanium tank filled with liquid xenon and cooled to minus 150 degrees Fahrenheit (minus 101 degrees Celsius). The xenon tank is surrounded by rock and a tank of water.
If a WIMP comes into contact with a xenon atom, it will emit light and electrons. The electrons are pulled upward and release more photons. By recording both the photons at the collision point and at the top of the tank, the detector is able to pinpoint the locations of the photon signals and measure their brightness.