
Originally Posted by
tomjin2000
But I still think the gravity between 2 objects can be affected by other objects.
As I know, Mr Newton didn't tell us the mechanism of Gravity. Can he really give us a valid equation to calculate gravity.
Well, it wasn't an "assumption", it was based on observation and has been confirmed by all observations since. Do you have a reason or evidence for suggesting that "the gravity between 2 objects can be affected by other objects"?
Of course, there are people who have looked at extensions to the model. Einstein, obviously, quite successfully. But also:
Milgrom, less successfully, with MOND.
Bekenstein's tensor–vector–scalar gravity.
Buchdahl's f(R) gravity.
Moffat's nonsymmetric gravitation.
Moffat's scalar–tensor–vector gravity
Sanders' bi-scalar tensor vector gravity
And several others. None of them are without problems.