There was definitely something like that - I am not sure if free-fall and being accelerated in a gravitational field are the same though. It may be that GR is talking about moving along lines in space-time that have the same gravitational potential (orbits), and moving across potential lines counts as an accelerated frame of reference in which you wouldn’t observe the same as in a reference frame moving at constant speed.
the equivalence of gravitational and inertial mass, and Albert Einstein’s observation that the gravitational “force” as experienced locally while standing on a massive body (such as the Earth) is the same as the pseudo-force experienced by an observer in a non-inertial (accelerated) frame of reference.
There was definitely something like that - I am not sure if free-fall and being accelerated in a gravitational field are the same though. It may be that GR is talking about moving along lines in space-time that have the same gravitational potential (orbits), and moving across potential lines counts as an accelerated frame of reference in which you wouldn’t observe the same as in a reference frame moving at constant speed.
I was thinking of the Equivalence Principle:
okay, but that would be an accelerated frame of reference, not equivalent to one that is “gravity free”