Why do stars experience gravity more than its mass?

[AshUchiha]

Gravity is an abstract concept. There is not "2 gravity" or "3 gravity". You cannot count a concept.If you would move half of Earth to somewhere else, the total mass of Earth would be the same, but you would feel a different gravitational force.For a point-like object, it works, for an extended object, it does not work.

There is no "truth" in physics, only good descriptions. Einstein's general relativity is the best model we have. Newton's laws are a good approximation to general relativity for all everyday situations.

Is it much like the nature of light? I mean we can't completely define gravity but we do have some theories which cover more or less about the phenomenon caused by gravity. Similar to light, we accept that it has dual nature because there is no other theory which best explains all the properties of light.

Also there are no proper units to explain the gravity experienced by an object in a universal scale... correct?
Then the law, g=Gm1m2/r^2 wont be applicable in all situations, right.

Basically we don't really know gravity but we use that equation just because it can help us to a certain degree?

 

[A.T.]

Basically we don't really know gravity but we use that equation just because it can help us to a certain degree?

This is true for all of physics.

 

[AshUchiha]

This is true for all of physics.

I don't think we can change the fundamentals of physics, can we? I mean if I can make a new theory that could replace newton's theory. Even then I would have to abide the fundamentals? Or can I come up with my own fundamentals which is also a good explanation of all the physical phenomenon

 

[russ_watters]

You can come up with whatever you want. Either it will work (match observations)or it won't. Newton's theory works well. Einstein's really, really well. You are unlikely to do better.

 

[A.T.]

Or can I come up with my own fundamentals which is also a good explanation of all the physical phenomenon

You have to make testable quantitative predication which fit observation better than current theories.

 

[sophiecentaur]

Evidence-based theory is ok. Theory based 'observations' are no good to a Scientist.