Does Antimatter Fall Up Or Down?

KentuckyFC writes "There are enough loopholes in the general theory of relativity to allow antimatter to fall up rather than down in a gravitational field. We've never been able to make enough of the stuff to do the experiment. But at the European particle physics laboratory at CERN, where scientists have been refining the technique for making antihydrogen, researchers are designing an experiment called AEGIS that will finally settle the matter. The idea is simple — fire a beam of antihydrogen atoms and watch which way they fall — but the details are fiendish (abstract). The answer should help solve a number of important conundrums such as why there is so little antimatter in our part of the universe and what the value of the cosmological constant is."

Comments

The answer is already known

[Ed Avis]

From the article:

The problem is that it's easy enough to trap antiprotons and positrons in electromagnetic fields. It's even fairly straightforwad to put them together so that they form antihydrogen. The problem is that antihydrogen is neutral and simply falls out of the trap.

This surely contains a clue about whether antihydrogen falls up or down...

Re:It will fall down

[oodaloop]

This got modded informative? Are you all retards? See my comment further downthread, or just google hydrogen escape velocity for yourselves.

Re:It will fall down

[Actually, I do RTFA]

You are thinking of neutrons.

Re:It will fall down

[oodaloop]

Hydrogen is both produced in our atmosphere and constantly bleeding away into space. It was also much more plentiful in the earth's past, and the vast majority of it has since escaped.