Special relativity has a weak spot that Einstein himself identified and addressed with General Relativity. But what is the weak spot?

If this above “equivalent” logic is valid, then what Einstein further inferred totally overturn Newton’s theory: when an object is free falling, Newton thinks the object is not in “static or evenly moving status” which seems to be intuitively acceptable for all of us, but Einstein would conclude – based on above “equivalent” logic – that the object has gravity pulling downward, and same time has the force pulling upward due to downward acceleration, hence the object is floating like in outer space, it’s in a typical “static or evenly moving status”.

What’s mind-boggling is that when the object is standing on a platform on earth, it has an acceleration hence not in “static or evenly moving”. The caveat here is that when the person stands on a platform, the platform provides a reverse “supporting force” which disappear whenever we move away from the adhering surface. So we are immersed in the “non-inertia” status, not “inertia” we mistakenly think of.

How to differentiate the actual “force/gravity field” and “felt-equivalent field due to acceleration”? in a large space, it’s possible as is demonstrated below, if you have a sufficient fine weighing scale, the measurements along the line does tell the difference.

Force and acceleration can be understood as equivalent as to how the object/human being feels, but they are difference. Concretely force can cause space and time warping but not acceleration….

Following the same line of thinking, one would ask the question if 惯性质量与引力质量 is equal? Newton already notice the difference and designed a pendulum to do the experiment

Einstein is very good at applying “thinking experiment”. We can see from above that from substituting himself into a free-falling object, he suddenly figured out the “non-inertia” status we are all in on earth. Now there is another famous experiment:

Imaging you sitting from far away versus sitting on the plate which is spinning, based on the special relativity, it’s easy/clear to conclude circumference of the plate is longer than before.

Based on the same reasoning, we can infer time runs faster in exterior and vice versa.