"The long term storage of significant amounts of antihydrogen should soon settle the question of whether antimatter falls up or down."
One reason they would like to know if antimatter is repelled by gravity is that it could explain why the Universe is expanding at an accelerating rate.[1]
Well, technically, it wouldn't be possible for a chunk of antimatter to be heavier than you.
But yeah, one theory is that if you hold one that's more massive than you are, its repulsion would overpower your attraction, and bang, zoom, straight to the moon!
Not sure if that conclusion is right. It probably wouldn't result in an explosion and the energy output would probably be in the form of light. Regardless, I'm going with Stephen Hawking on this one: "If you ever meet your anti-self, don't shake hands!"
"It probably wouldn't result in an explosion and the energy output would probably be in the form of light."
That's what nukes do too. Turns out that dumping absurd amounts of light (various parts of the spectrum, but certainly including visible) into the surrounding area absurdly fast tends to fuck stuff up pretty good.
Funny that I actually managed to get the maths wrong. 4000 TeraJoules is 4 PetaJoules, i.e. 10g of antimatter is actually a 0.25 Megaton nuke. Still packs some serious punch, but I totally fail at arithmetic, it seems.
"The long term storage of significant amounts of antihydrogen should soon settle the question of whether antimatter falls up or down."
One reason they would like to know if antimatter is repelled by gravity is that it could explain why the Universe is expanding at an accelerating rate.[1]
[1]: http://www.physorg.com/news/2011-04-antimatter-gravity-unive...