[smosher]

I think the "falling up" argument comes from the conception that antimatter is the time-reverse of matter.

[machrider]

Of course, regular old hydrogen "falls up", being lighter than air. :) I guess if gravity is truly reversed for antihydrogen, it would fall up even faster. But I highly doubt it's actually gravitationally repulsive.

[smosher]

The simple solution is to let it fall in a vacuum, which seems to be what they're doing in this case.

[delinka]

Or perhaps must be affected by antigravity the way matter is by gravity. Assuming antigravity exists. Whether that's correct at all I don't know, but that's the logic being used.