Physicists just confirmed one of the last untested predictions of Einstein's general relativity — antimatter falls downward under gravity at exactly the same rate as normal matter, ruling out the possibility of antimatter antigravity that decades of unresolved theoretical physics had left as an open possibility.

 

Physicists just confirmed one of the last untested predictions of Einstein's general relativity — antimatter falls downward under gravity at exactly the same rate as normal matter, ruling out the possibility of antimatter antigravity that decades of unresolved theoretical physics had left as an open possibility.

The ALPHA-g experiment at CERN created antihydrogen atoms and released them in a vertical magnetic trap to directly observe their gravitational behavior under controlled conditions. Of 754 antihydrogen atoms released, 78 percent fell downward — statistically consistent with normal gravitational acceleration, confirming antihydrogen falls identically to regular hydrogen atoms in every tested condition.

This result confirms the equivalence principle — the very foundation of general relativity — holds for antimatter as well as ordinary matter, significantly constraining models proposing exotic gravitational interactions. It closes a fundamental open physics question pursued since antimatter was first produced in laboratory conditions in the 1950s.

Source: ALPHA-g Collaboration CERN, European Research Council, Nature Journal, 2025

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