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I know and understand about the fact(?) that there is no experiment/ instrument that could tell if the instrument is in a accelerating box in free space or it is in a box that is sitting on the ground on some gravitating object. .. but one instrument bothers me a bit - atomic clocks measuring time dilation at different heights above the ground. That is, I have red that some super precise clocks have been made that can measure the time dilation of just few meters.Cant a atomic clock tell the difference of accelerating box or gravitating object? That is - there would be no such time dilation in the box?
Hmm, yes, tidal forces, thats kinda the same thing - difference in strength of gravity = difference in flow of time.Now im even more confused - why is there time dilation in accelerating frame but no tidal effect?
Now im even more confused - why is there time dilation in accelerating frame but no tidal effect?
A uniformly accelerating frame of reference is equivalent to a uniform gravitational field.
One would need fairly sensitive equipment to observe this (or measure over very large distances), but:..
Quote from: chiralSPOOne would need fairly sensitive equipment to observe this (or measure over very large distances), but:.. Thatís true. However it should be noted that such extremely sensitive instruments do exist and have been in use since at least 2006. The one I know of is called an Electrostatic Gravity Gradiometer] and itís roughly the size of a breadbox and can make a measurement in a fraction of a second. It can detect differences in acceleration as small as 10-10cm/s2 over a distance of 50 cm, that is a gradient of 2x10-12/s2.A good account of all of this is in my article Einsteinís Gravitational Field which is online athttp://xxx.lanl.gov/abs/physics/0204044
The equivalence between accelerating and being in a gravitational field is often expressed as "an observer in a small box" (read: microscopic box).Tidal effects are mostly visible over larger areas.