CERN Physicists Create Antimatter (and Could Build a Bomb in a Billion Years)
Nov 18, 2010 12:04 PM PT
Physicists at the European Organization for Nuclear Research (CERN) in Geneva have created the stuff of "Star Trek" for the first time ever: genuine antimatter.
A 17-member team announced the production and preservation of 38 antihydrogen atoms. Physicists Emilio Segre and Owen Chamberlain of the University California, Berkeley, earned the 1959 Nobel Prize for producing part of an antihydrogen atom, antiprotons.
"We've overcome the last important hurdle in the quest to do precision experiments on the antihydrogen atom, a goal for 20 years," CERN co-investigator and Auburn University physics professor Francis Robicheaux told TechNewsWorld. "It was an incredibly difficult undertaking to trap antihydrogen."
Science Fiction Becomes Fact
The physical and mathematical opposite of matter, antimatter first emerged in a series of elegant equations formulated by the Nobel Prize-winning physicist Paul Dirac in 1928. Like so many mathematically predicted particles -- strings and quarks among them -- antimatter has until now existed only on paper.
The simplest type of atom, a hydrogen atom -- the matter version -- consists of one negatively charged electron orbiting one positively charged proton. The antimatter version is the simple opposite -- a positively charged anti-electron, the positron, orbiting a negatively charged antiproton. When they collide, matter annihilates its antimatter twin.
The news that scientists have created antimatter should be welcome to science fiction devotees as well. "Star Trek" aficionados will remember that energy generated when matter and antimatter collided sent the Starship Enterprise into time-warping speeds. Angels and Demons author Dan Brown, best known for The Da Vinci Code, had fictional hero Robert Langdon chasing a secret society bent on destroying Vatican City with an antimatter bomb.
Known as the "Alpha Experiment," the CERN team's antimatter project had a simple goal, said CERN investigator Jeffrey Hangst from the University of Aarhus Department of Physics and Astronomy in Aarhus, Denmark.
"We wanted to see if matter and antimatter behaved identically, as predicted by Dirac," Hangst told TechNewsWorld.
However, this question remains incompletely answered. A product of the Big Bang theoretically produced in abundance, antimatter didn't survive whatever powerful evolutionary pressures permitted the matter we see all around us to reign supreme. As a result, it must be coaxed, very carefully, into existence.
To produce antimatter requires the absurdly low temperature of 1/2 degree above absolute zero -- that is, -273.15 degrees Celsius, below which temperatures cannot be reached using methods available to mortals -- and ultra-sensitive signal detection, Hangst explained. What's more, the antimatter lasted for roughly one sixth of a second before Mother Nature -- and normal matter -- annihilated it.
"The forces holding antihydrogen atoms are so feeble the atoms need to be incredibly cold or they are too energetic to hold," Auburn's Robicheaux explained. "It is a tribute to the skills of my experimental colleagues that we were able to make several innovations that were never tried with antimatter, and several that had never been tried even with matter."
Also in tribute to those skills, biographer Graham Farmelo -- author of The Strangest Man: The Hidden Life of Paul Dirac -- "sent me a note of congratulations," Hangst said. "He said Dr. Dirac" -- who died in 1984 -- "would have been proud."
Angels and Antimatter
To continue antihydrogen experiments, scientists still have to reach two important milestones, explained Rolf Landua, a CERN physicist not involved in project Alpha whose project Athena started the push to produce antihydrogen in 2002.
"They have to make lots of antihydrogen atoms, and they have to capture these antihydrogen atoms in sufficient numbers for a reasonable time," said Landua. "In another year or two of fine tuning, this might be possible."
Indeed. Since announcing the results, "we've vastly improved the trapping efficiency and the length of time the atoms are trapped," Robicheaux noted.
Landua -- who was Dan Brown's model for fictional CERN physicist Leonardo Vetra, murdered for his antimatter expertise -- told TechNewsWorld that while Brown's science was accurate, his plot was too far-fetched by about a billion years.
"To make the bomb in Angels and Demons, they used about one gram of antihydrogen," Landua said. "But even with all the efforts at CERN and elsewhere, it is very hard to even produce one billionth of a gram of antiprotons per year."
Several more steps -- from cooling and capturing the antiprotons to recombining them with positrons -- "make the best of all cases one billion years to make one gram of antihydrogen," Landua said. "That's too long to wait -- even for the most enthusiastic Dan Brown fans."