Wednesday, October 11, 2006

Matter/AntiMatter Molecule Created

Scientists at CERN, a giant particle accelerator straddling the border between France and Switzerland, have created the first molecule made of both matter and antimattter.

The researchers made the molecules by slowing antiprotons and letting them interact with hydrogen molecules, leading to molecules consisting of a single proton bound to a single antiproton, as well as leftover hydrogen atoms.

(Bear in mind that scientists have long ago managed to join electrons and positrons together into positronium, which is a lot like a molecule, but molecules really should have atoms in them, rather than just electrons and their antimatter positron partners.)

The researchers reported their work in this week's edition of Physical Review Letters.

Now the big question -- what do we call the stuff?

The CERN folks are going with "antiprotonic hydrogen." A bit hard on the tongue, I think.

My friends at Physics News Update (PNU), who reported the story first, like "protonium." That's probably the best bet, but if we are following convention established with positronium (which is named after the antimatter particle), it should be called "antiprotonium."

Wikipedia already has an entry for protonium, so I think my PNU friends have made the right call.

Regarding the graphic above, you can't really take pictures of atoms and small molecules, but these shapes (spherical harmonics) are closer to the way hydrogen atoms would actually look if you could see them. If CERN releases images of protonium/antiprotonium/anitprotonic hydrogen, I'll post those instead.


  1. It's called dylithium!!! :-)

  2. How is it possible to create a molecule consisting of both matter and antimatter? What wikipedia says is that interaction of particle and antiparticle results in a big boom. That made me wonder :D

  3. I know. It's weird that protonium sticks around at all.

    If you check out positronium on Wikipedia you'll see that an electron and an anti-electron (positron) can also hook up for a while before they anihiliate.

    The following is a flawed sort of analogy (because it's based on an old-fashioned picture of particle motion), but the two particles don't anihilate so long as they orbit each other. If the moon were made out of antimatter it wouldn't be a problem provided it stayed up there in orbit.

    Quantum mechanically, I believe, you would say that so long as their wave functions don't overlap much, the chances of the proton and antiproton anihilating each other is small.

    Even so, the protonium molecule does go boom in about a thousandth of a second.

    But that is still a relatively long time. If they weren't in orbit around each other, they would only last a trillionth of a second before they went pop.