Antimatter: ISOLATED!

[Anomalocaris]

Great article though I would have liked it to brush upon Baryon asymmetry in more detail, antimatter itself is no mystery to us, but the absence of it (at least they mentioned that) in the universe lacking an explanation is a major unresolved problem in physics.

Anyway, the article says that they are only trapped for a tenth of a second. Do the antihydrogen atoms escape the magnetic field and annihilate with the hydrogen or do they decay into smaller particles?

Trying to preserve any amount of concentrated antimatter in electromagnetic traps for any length of time is incredibly difficult, when making antiprotons, they're negatively charged and so they repel away from each other into the container (matter) and annihilate upon contact.

I thought they made hydrogen atoms which meant a antiproton plus a positron, so the whole the is electrically neutral.

[Welsh cake]

I thought they made hydrogen atoms which meant a antiproton plus a positron, so the whole the is electrically neutral.

Antihydrogen is the counterpart of hydrogen, while hydrogen's particle is positively charged its opposite antimatter has a negatively charged. Antihydrogen has a positive electron (antielectron) and a negatively charged positron (antiproton).

Antihydrogen's electron has the same size and weight as Hydrogen's electron, it is perfectly stable, the only difference is the two, antimatter and matter, have opposite charges.

You are confusing antiprotons with anti-neutrons, the antiparticle of a neutron, which is electrically neutral, the only difference is that it spins in an opposite direction.

A hydrogen atom (matter) composes of just one electron and one proton, whereas the antihydrogen atom (antimatter) is made up of only a positron and antiproton. Hydrogen does NOT have a neutron, antihydrogen does NOT have a anti-neutron.

[Anomalocaris]

No, I am afraid you appeared to have said the samething i did, but much more confusedly. Whether it is a hydrogen atom or antihydrogen atom, it is neutral. The charge of the electron and the charge of the proton cancels each other in the case of hydrogen, and the charge of antiproton and the charge of positron cancels in the case of anti hydrogen. In both cases the atom is neutral while it's nucleus is not. Neutron plays no part.

In fact this applies to all atoms, not just simple hydrogen. All atoms are neutral until ionized, when loss of electrons or positrons allows the charge of the nucleus to be manifest.

Thus antihydrogen atoms do not repulse each other due to the like charge of their nuclei, nor can they react to magnetic containment through the overall charge of the atom. Instead they react because the different spacial distribution of the charges in their nuclei and the charge in their electron, or positron clouds.

[orogenicman]

I will point out that hydrogen is in herently unstable, which is why in nature, it is found as dihydrogen (H2). So the question is does this feature also exist with anti-hydrogen. In other words, does it also have the tendency to form anti-dihydrogen in a "stable" environment?

[Anomalocaris]

The atom hydrogen is stable, this is why most of the hydrogen formed in the big bang is still around. That they form into molecules is an artifact of their electron clouds. In this two antihydrogens should exhibit the same affinity as two normal hydrogens.

[Welsh cake]

No, I am afraid you appeared to have said the samething i did, but much more confusedly. Whether it is a hydrogen atom or antihydrogen atom, it is neutral. The charge of the electron and the charge of the proton cancels each other in the case of hydrogen, and the charge of antiproton and the charge of positron cancels in the case of anti hydrogen. In both cases the atom is neutral while it's nucleus is not. Neutron plays no part.

In fact this applies to all atoms, not just simple hydrogen. All atoms are neutral until ionized, when loss of electrons or positrons allows the charge of the nucleus to be manifest.

Beg your pardon, I didn't realise you were talking about the antihydrogen atoms themselves and not the actual particles, yes you are quite correct, anti-atoms are electrically neutral.

Thus antihydrogen atoms do not repulse each other due to the like charge of their nuclei, nor can they react to magnetic containment through the overall charge of the atom. Instead they react because the different spacial distribution of the charges in their nuclei and the charge in their electron, or positron clouds.

We don't yet know. It hasn't been empirically proven or disproven if antimatter has negative gravitational mass or not, which is unlikely, but we haven't created enough anti-atoms to understand the interactions of antimatter or devised a technological mean to suspend them in a perfect vacuum so they don't drift out of the trap and therefore survive long enough to test this.

[Anomalocaris]

I've seen no theoretical suggestions that antimatter possesses negative gravity. In any case, gravity is so negligibly weak on the atomic and molecular scale compared to electromagnetic force so its effects won't impact thing much.

[Welsh cake]

I've seen no theoretical suggestions that antimatter possesses negative gravity. In any case, gravity is so negligibly weak on the atomic and molecular scale compared to electromagnetic force so its effects won't impact thing much.

There are currently three theories on the gravitational interaction of antimatter, all three lack experimental evidence:

http://en.wikipedia.org/wiki/Gravitation...antimatter