Hi You guys probably have heard about the monkey and hunter problem. Basically in the monkey an hunter problem you can see the dart hits all the time if you observe the experiment in an accelerated frame of reference ie your falling with the monkey. You see the bullet travel in a straight line and the monkey stationary. The collision occurs exactly at the same time for both accelerated and stationary frames of reference Basically i modified it slight with this thought experiment. - Pretend the monkey is very small - instead of firing a dart fire a very small pulse of light like a photon. Observing from the 1st frame of reference you see the pulse miss the monkey it travels in a straight line and the monkey drops a bit In the second accelerated frame of reference The the pulse of light can either travel in a parabola if you apply the frame of reference transformation rules ( adding -g to every object), which doesn't make sense since light cannot accelerate Or the pulse of light will travel in a straight line and this time HIT the monkey since the monkey is stationary in the accelerated frame of reference therefore the frames of reference are no longer equivalent. Implying a relation ship between gravity space and time for equivalence to hold... dunno if this leads to general relativity...?