Quote:
Originally Posted by renormalised
It does bend space a little more, but the effect is so small that it only becomes important on very large scales...like planetary size and greater. However, if you were to drop Jupiter and the Earth into the Sun, they would both fall into it at the same acceleration if they were dropped from the same height/distance. Both would hit at the same time. Just to show you, get a glass and an USB stick, stand over a soft chair or sofa, hold both at about the same height, then drop them into the chair. You'll see they both hit the chair at roughly the same time. Now, vary which one is further away from the chair and repeat the experiment, see what you get and come back here to report what you see  |
Thank you for posting a very helpful reply
.
With respect Carl terms such as " a little more" and "so small" make me feel I have made a reasonably valid point
, however it is not science unless we are specific in quantifying how much "a little more" and "so small" represents by measurement (conducted upon many samples
) but I suspect in relation to the 1 gram v the 1,000,000 gram question that any measurement presumably would be beyond the capabilities of current human endeavour ...although when I read articles announcing that GR has been "proved" to operate even at measurements as low as billionths of an inch I do wonder if there is any limit on our ability to observe "small"...
I think that the glass and the chair etc suggestion leaves us with a rather slack experiment
... holding the objects at
about the same height offends my desire to eliminate areas that could corrupt any observation..we need to drop from exactly the same height
.and as to both hitting at "roughly the same time" this is far to loose as we need to know if they hit at
exactly the same time or
not at exactly the same time
.
However your suggestion there is benefit in observing what actually does happen appeals greatly to my "learn by observation" approach to the universe and in this regard I propose that it is only by dropping our two test objects from a great height and observing what actually happens and taking great care not to have a preconceived view of the outcome...that we can know for sure.
I guess the point I am making that the observations we take with absolute acceptance..namely that irrespective of mass objects fall at the same rate.. could reasonably be regarded as suspect ...and that observations conducted where objects fall over greater distances should be made and the results analyzed.
I look at the matter in this way because my understanding of the general premise given to us by GR ...that mass alters space time and it is this relationship that we currently express as gravity... although what it seeks to do is simply describe a relationship between frames of reference ..and I think that is what you pointed out in your reply.
AS you pointed out GR has an element of "what the observer experiences" however it seems to me that we have to fit the general premise into a reality suggested by it...or as difficult as it may seem to except it could be that our fundamental "belief" that things fall a the same rate irrespective of mass was never put to a reasonable test (involving the distances GR would need) and the results observed. Observation over a chair or from the tower at Pizza may not be grand enough to demonstrate the belief may be flawed.
Certainly we can say things fall at the same rate if we observe only over relatively small distances, as no doubt we have been restricted to) and I suspect that if any differences in the rate of fall have been observed the difference was simply put down to air resistance or whatever because we already know things fall at the same rate...
So if we are to be sure of what happens we need to drop the test articles from a great distance and mask out things that may corrupt the result..air resistance for example...
I submit that such an experiment may show our current belief to be flawed even if only just a little
alex