It would make sense if gravity is the same for antimatter and regular matter. But there is no direct evidence proving this. Scientists who work with CERN's ALPHA experiment, an antimatter experiment, tried to measure it in a somewhat roundabout way. First the researchers made antimatter, by joining antiprotons with positrons--the opposites of protons and electrons, respectively--and producing atoms of antihydrogen. The anti-atoms were suspended in a strong magnetic field so they wouldn't touch the walls of their container, annihilating themselves and their counterparts.