Antimatter does not “fall up”, but rather responds to the gravitational pull of the Earth in much the same way as normal matter. That is the conclusion of physicists working on the ALPHA-g experiment at CERN, who have made the first direct observation of free-falling antimatter atoms.
The experiment helps rule out the idea that a difference in their responses to gravity is somehow responsible for the fact that there is much more matter than antimatter in the visible universe. However, the measurement still leaves open the tantalizing, but very unlikely, possibility that antimatter and matter react slightly differently to gravity.
To read more, click here.