Answer: Acceleration in space and gravity on Earth have the same effects on objects.
Step-by-step explanation:
General Relativity theory was formulated by Einstein and is based on three principles:
1. Covariance
2. Equivalence
3. The curvature of space time
Now, talking in this case about the equivalence principle, Einstein formulated the following:
A gravitational force and an acceleration in the opposite direction are equivalent, both have indistinguishable effects.
Hence, for general relativity, gravitational force and acceleration in the opposite direction have the same effect, even for light.
This is better understood if we deal with gravity not as a mysterious atractive force but as a geometric effect of matter on spacetime.
In other words: When matter occupies a region of spacetime, it causes its deformation. So, since all objects and bodies (including us) move in this space-time, when this warps due to the presence of matter, their trajectory will be diverted producing their acceleration.