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EVERYTHING falls the same, from the lightest feather to the heaviest star. That’s part of the foundation of Albert Einstein’s theory of general relativity. Now, observations of three stars orbiting one another have confirmed that it holds up even for some of the heaviest objects in the universe.

An object is in free fall when the only force acting on it is gravity. The strong equivalence principle, a pillar of the theory of general relativity, has it that all objects subject to the same gravitational forces should fall at the same rate, even if their masses differ.

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