May 14, 2009 at 9:50 PM ET
|Click for video: Watch |
a clip from "Angels and
Demons" that explains
how the (fictional)
antimatter bomb works.
The good news is that you don't have to worry about an antimatter bomb blowing up the world. Physicist Michio Kaku says so. The better news is that the antimatter being made at Europe's CERN physics lab is used for good, not for evil.
The physicists who do real-life research with antimatter and other exotic substances see "Angels & Demons" not as a threat but as an opportunity. CERN is just one of the scientific institutions to capitalize on the "science behind the story."
The US/LHC research group has organized an entire lecture series around the movie, including virtual lectures you can watch on the Web. And at 1 p.m. ET next Tuesday, the National Science Foundation will present a Webcast featuring CERN's director-general, Fermilab's Boris Kayser and Nobel-winning physicist Leon Lederman - who literally wrote the book on "The God Particle."
CERN has been through this before, back in 2000 when "Da Vinci" author Dan Brown's book version of "Angels & Demons" came out. "The hits on our public Web site went up by more than a factor of 10, and I guess this will happen again now that the movie is coming out," said Rolf Landua, who led the research team for the ATHENA antimatter-making experiment at CERN.
That experiment didn't take place at the Large Hadron Collider, but at CERN's antimatter factory, more formally known as the Antiproton Decelerator. "We can make antimatter, we can slow it down to almost zero speed, we can trap it, we can manipulate it. But that's it," Landua told me.
Antimatter has been called the "evil twin" of ordinary matter. In ordinary atoms, negatively charged electrons swirl around positively charged protons. In antiatoms like the ones that Landua and his colleagues made, positively charged antielectrons, or positrons, orbit nuclei that contain negatively charged antiprotons. If atoms of matter and antimatter come into contact, they annihiliate each other, just like they do in "Angels & Demons" - or, for that matter (heh, heh), "Star Trek."
|This is an image of a matter-|
antimatter annihilation in the
ATHENA experiment at CERN's
Antiproton Decelerator. Yellow
tracks indicate pions produced by
the antiproton, and red tracks are
gamma rays from the positron.
So if scientists can really make antimatter, why couldn't they create an antimatter bomb, or at least a new source of energy? Landua explains that it takes about a billion times more energy to make antiatoms than the energy you get by destroying them. This is why antimatter is considered the most expensive material on Earth. A commonly quoted figure is that it costs $1.75 quadrillion per ounce - and although that figure may be subject to debate, the bottom line isn't: No one could afford to make enough antimatter to cause trouble.
Then there's the problem of keeping the antimatter around once it's made. The antiatoms that Landua and his successors at CERN have made tend to drift out of the "traps" where they're created and quickly blip out of existence. "It's still not completely clear what atomic state they're in when they're made, and what their kinetic energy is," Landua told me.
OK ... so if you can't keep those antiatoms together, and if they cost so much to make, why make them at all? The main reason is to study why it is that matter won out over antimatter in the universe's earliest moments. The traditional view holds that matter and antimatter should be perfectly matched, and that they should annihilate each other so totally that nothing would be left but a cosmic sea of light.
"That would have happened to the whole universe," Landua said. "It happened almost, but a little bit of matter was left - only a tiny, tiny bit - which now makes up all the stars, planets and us."
Previous experiments have suggested that there is a slight asymmetry in the way that matter and antimatter decay. One of the LHC's experiments, known as LHCb, will look specifically at that issue once the big collider is started up this fall. "It has nothing to do with an energy source, or 'Star Trek,'" Landua said. "It's a basic, fundamental science question, which is coupled to the question of why we are here."
There are practical applications for antimatter, but they have more to do with medicine than propulsion physics. For example, positrons are used routinely in PET scans to trace the inner workings of your body.
In the future, antimatter might be enlisted in the fight against cancer. One experiment indicated that beams of antiprotons were three times as efficient as protons for destroying tumor cells in hamsters. If that technology could be harnessed for radiation therapy, "it looks like you could reduce the radiation to healthy cells by a factor of three," Landua said.
Today, the cost factor is working against antiproton therapy, but Landua said new technologies could bring the cost down - not low enough for bombmaking, but low enough for cancer-killers. "Maybe one day there will be different types of accelerators based on laser wakefields," Landua said. "I'm waiting for the development of powerful Lyman-alpha lasers. That should be the way to go."
For now, Landua and his colleagues can sit back and enjoy the Hollywood wizardry in "Angels & Demons." He and about 50 other scientists from CERN saw the film during an advance screening in Geneva. "They were all really enthusiastic about it," Landau said.
Some of the details weren't quite right: For example, the film shows scientists sitting just on the other side of a window from the LHC's ATLAS detector. In real life, anyone sitting that close to the beam would get a withering dose of radiation. And there's no way the beam would come to full power as quickly and easily as it does in the movie. But Landua, like most scientists, understands that this is Hollywood rather than real life.
"It was so for real, you know?" Landua said. "You see these ATLAS caverns and it integrates so perfectly well that you think, 'My God, is that reality? Did I miss it?' ... We wish we could work at a place which looks like that CERN."
Here are a few extra tidbits to enhance your "Angels & Demons" experience:
Update for 2:15 p.m. May 19: Particle physicists provided an additional reality check during the National Science Foundation's Webcast - including confirmation that a few things in "Angels & Demons" are actually true. For example, could a quarter-gram of antimatter set off an explosion with the energy equivalent of 5 kilotons of TNT? After running the numbers, Fermilab's Boris Kayser says yes, indeed. "I get 5.7," he said.
CERN's director-general, Rolf-Dieter Heuer, said the physics lab does have an eye-scanning identification system for controlling access to the Large Hadron Collider, as graphically shown in the movie. It's that important to know exactly who is in the vicinity of the collider when it's running, he said.
I asked the physicists about the friendly competition between CERN and Fermilab to find the first evidence of the Higgs boson's existence. Heuer emphasized that the rivalry was not of the tooth-and-claw variety: "I don't mind ... who makes a discovery first. It is the science that counts."
But there is a rivalry, nonetheless. Heuer said the probability for Fermilab finding the Higgs first was "not very good, so I'm still sleeping pretty well."
Nobel laureate Leon Lederman is based at Fermilab but has done a lot of work at CERN as well. Like many physicists, he has divided loyalties - and he guessed that he would experience mixed feelings if Fermilab's Tevatron beat the shiny new, $10 billion Large Hadron Collider in the Higgs race. He joked that it would be "a little like your mother-in-law driving off a cliff in your BMW."