Some Antimatter Questions

Most recent answer: 10/22/2007

what’s antimatter? What’s it useful for? is it a good energy source? How do you create antimatter?
- Socrates (age 13)
Hi Socrates,

Please look at our other answers on Antimatter to find out what it is and how it is created. Antimatter isn’t really commercially useful, but producing it in physics laboratories and studying it helps us understand the particles, forces and symmetries of nature. One big, important question is: "Why doesn’t antimatter behave exactly the same way as matter?" Understanding the answer to that question helps us understand the answer to "Why is most of the stuff we can see in the universe made of matter -- where did all the antimatter go?"

In high-energy particle collisions, equal amounts of matter and antimatter are created. We suspect that the same things happened shortly after the big bang, some 14 billion years ago. But somehow, a small difference in how the matter and antimatter behave left the universe with a tiny excess of matter, and when the matter and antimatter annihilated, just a tiny fraction of extra matter was left over -- enough to produce all the visible stuff in the universe. We’d like to understand how all that happened, and so we create some of it in the lab in high-energy collisions.

Is it a good energy source? No, not really. It’s more like an energy storage medium -- it takes energy to make the stuff, and you get your energy back when the antimatter annihilates with ordinary matter. It’s very inefficient to do this -- the collisions may radiate extra photons, many of the high-energy particles won’t collide but will miss their targets, and storing antimatter takes special magnets and radiofrequency cavities, all of which take lots of energy to run. It’s a good way to use up energy!


(published on 10/22/2007)