# A few questions about gravity

something = z+r2

F=ma, true but i understand it better explained like; force equals the measured mass of an object multiplied by its rate of acceleration.

anyways, why are gravitational fields infinite?
How do we know they are infinite?

Infinite in what way?

K^2
I'm going to assume you mean infinite range. In classical gravity, gravitational field line can only start or terminate on a mass. So gravitational field will always extend out to infinity. This works because classical gravity is a low-energy approximation to General Relativity. And we don't really know why General Relativity holds. It's either just how the world works, or it's an approximation to an even more complex theory. But then we wouldn't know why the later holds either.

Anyways, we can't test this directly, of course. We cannot measure gravity from an object that's on the far side of the universe from here. But we can test whether the theory itself holds, and then we make an assumption that it holds at any range.

Yes, the range of the gravitational field is by modern physics considered infinite.

I'm not saying its wrong i'm just saying i personally without a education in physics, don't like that concept.

Over time we have developed a lot of things to try and understand gravity
a gravitational constant, a pattern gravity fallows 1/r^2, theories like gravitons.
I feel like were missing something very simple which makes our calculations wrong in the big end results.

K^2
While it's possible that long-range interaction somehow behaves differently, we have no good indication of that. On the contrary, we have very strong indication that General Relativity works. It gives extremely accurate predictions for certain phenomena. I don't want to discourage anyone from looking for alternative explanations, but they would need to make testable predictions that are distinct from GR, as well as explain why tested predictions of GR work so well.

Anything we know can be wrong. In fact, it's probably wrong. But ultimately, what we care about are predictions. If a theory makes predictions that work, we like that theory, and we are going to treat it as "this is how things work," even in situations where we know otherwise.

K^2
While it's possible that long-range interaction somehow behaves differently, we have no good indication of that. On the contrary, we have very strong indication that General Relativity works. It gives extremely accurate predictions for certain phenomena. I don't want to discourage anyone from looking for alternative explanations, but they would need to make testable predictions that are distinct from GR, as well as explain why tested predictions of GR work so well.

Anything we know can be wrong. In fact, it's probably wrong. But ultimately, what we care about are predictions. If a theory makes predictions that work, we like that theory, and we are going to treat it as "this is how things work," even in situations where we know otherwise.

Drakkith
Staff Emeritus