Scientists Trap Antimatter for the First Time
No matter. The point is, the equation works both ways: energy can become mass. However, as physicist Rolf Landua explains in his TED-Ed video: “Like two currencies with a huge exchange rate, 90 trillion joules of energy are equivalent to 1 gram of mass.” So, more energy than was released by the Nagasaki bomb would be needed to form something the size of a paper clip. We do not have the means to do this, but CERN comes close.
Based near Geneva, Switzerland, CERN is the European Organization for Nuclear Research. It also happens to be the birthplace of the World Wide Web, so you can thank it for your ability to read this article in the first place. But let’s not digress. In relation to our topic, CERN operates the largest particle-physics laboratory in the world. All its machines are engaged in answering the question, “What is the universe made of?”
Matter and antimatter
Particle physics says the universe is made of matter and antimatter. Now, we all know about the Big Bang theory, the phenomenon that created all matter in the universe. So where does antimatter come in? Enter Paul Dirac, author of a less-celebrated equation.
In physics, matter consists of atoms, and atoms consist of particles such as protons and electrons. Protons carry a positive electrical charge while electrons carry a negative one. Based partly on Einstein’s equation, Dirac predicted that every particle in the universe has a twin, an anti-particle with reversed electrical charges. As the CERN website explains, this is “just as the equation x2 = 4 can have two possible solutions (x = 2 or x = -2).” Matter, antimatter. Dirac was proved right and won the 1933 Nobel Prize.
It may sound like science fiction, but according to Symmetry magazine, the average banana emits an anti-electron (called a positron) every 75 minutes due to the potassium atoms inside it. However, when antimatter touches matter, they both annihilate – poof! Mass converts to energy. This is what happens to banana positrons when they collide with electrons in the air.
Now, by the same logic, we all shouldn’t exist. The Big Bang should have produced equal amounts of matter and antimatter, which should have destroyed each other and left nothing but energy. Yet here we are. Clearly, there is more matter in the universe. There’s more to antimatter than is suggested in Dirac’s equation, and that is what drives particle physics.
Taking antimatter into their hands
CERN has been an “antimatter factory” since 1995, when its scientists created nine atoms of antihydrogen. Hydrogen has the simplest structure in the universe – one electron orbiting one proton – so its antiatom was the easiest to produce. Not so easy was holding on to them long enough to learn more about antimatter. Seven years later, two other experiments synthesized more antihydrogen atoms, but still only fleetingly.
On November 17, 2010, the ALPHA team figured it out. For the first time ever, they held 38 antihydrogen atoms in place using a container made of magnetic fields. This trapped the antiatoms for 172 milliseconds – a blink of an eye to us, but long enough for the scientists to consider the stuff. They did even better the following year, holding antihydrogen atoms for no less than 16 minutes.
So why does antimatter matter so much?
Some think it could fuel rockets or blow up cities, as imagined in stories such as Star Trek, Avatar and Angels and Demons. However, antimatter isn’t an energy source waiting to be mined; we manufacture it ourselves. What’s more, according to Symmetry, all the antimatter we’ve produced “wouldn’t even be enough to boil a cup of tea.” The energy put in wouldn’t be worth the output – catastrophic explosion; tiny little paper clip.
As a matter of fact, the ACE team at CERN is studying antiprotons for use in cancer therapy, not weaponry. Yet, mostly, physicists just really want to know why there’s less antimatter in the universe than they’ve calculated there should be. How did it disappear? Is it the same as matter? Does it react differently to light, or to gravity? In what ways? There are still so many questions, but presumably the outcome will one day be worth all the effort.
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