Why does gravity get weaker with distance?

[Glaran K'erman]

Dark magic, clearly.

[Darnok]

Yep, earth is affected by the gravity of every object in the observable universe. However, most of them are too far away to have any measureable effect.

Subatomic particles are dominated by forces many orders of magnitude stronger than gravity, acting over far smaller distances, so I think it's fairly safe to say that the gravity of distant objects has a negligibly small effect over, say, the motion of electrons.

Look at image posted by @SuperFastJellyfish and now if gravity from Kepler star or planet would pull only single particle of your body (A and greatest distance) then of course you wouldn't even felt that. And of course every other body in universe would be pulling some other particle of your body, while Earth, being so close, should pull every particle of your body... that is why you don't hover over Earth

Answer to OP would be... no gravity is not getting weaker over distance just the closer studied objects is to the other object then more gravitational wave/particles is "hitting" more particles of object. If you increase distance between two bodies then less gravity waves is pulling those bodies, but they are not weaker, they have same strength as those send from very close object.

If we would allow photons from Kepler star to hit particles inside LHCE then energy from single collision should be same as energy from collision of photon send from Sun, of course it would be less collisions from photons from Kepler star. Same thing should work with gravity, if we would be able to shield particles in LHCE in way that only Earth garvity and Kepler star is affecting them, then those particles trajectories should be shifted by Kepler star.

Of course we can't shield objects from gravity wave and every particle is being pulled by every object in space from every possible angle, yet those far forces are as strong as Earth gravity, but they are at balance and they are affecting only small portion of particles compare to Earth that is affecting all of our particles.

At least this is how I understand gravity taking assumptions made by Newton and Einstein (I think they both were wrong, but explaining that would be much more complicated ).

[Jim DiGriz]

My guess is that it behaves like a wave when traveling and like a particle on its arrival.

A Quantum Theory of Gravity is going to behave very similar to EM in the same way that photons of light are both particles and waves, gravitons are also both particles and waves. All the same principles will apply, there's nothing conceptually different there -- its the same problem of quantum wavicles that you can get with a two slit experiment using photons or electrons. Where it gets different is that gravity is tensor field and graviton would be a spin-2 particle (and would be an extremely light particle due to gravity being very weak), and also due to gravity self-interacting and being nonlinear.

[Camacha]

Dark magic' date=' clearly.[/quote']

That makes the trinity complete, together with dark energy and dark matter

[GeneralVeers]

So we know that gravity is a wave.

Not exactly. The term "gravitational wave" isn't referring to gravity itself--it's referring to the force gravity exerts. When a massive object passes by you, its gravitational pull changes in a way analogous to a wave, hence the term. By way of analogy: a flashlight emits photons, but that doesn't mean a flashlight IS a photon.

There's been a lot of talk in here about whether gravity itself is a particle (i.e. a graviton) or a wave, and I say it can't be either. For this reason: gravity, as we have observed plentifully throughout history, passes right through solid objects without being affected by them. The Moon's gravitational pull on you, right now, is a function only of the Moon's mass, your mass, and the square of the distance between you and the Moon. The Moon's force on you is NOT affected when the Moon is on the far side of the Earth and its gravitational pull is going through the Earth to reach you.

This doesn't square with the behavior of particles at all. There's nothing I know of in the entire universe that can interact with something and at the same time be entirely unaffected by it (the closest we've gotten is the neutrino, which is almost entirely unaffected by matter and at the same time has almost no effect on it). Further, normal particles, when they hit something and interact with it, must expend energy. That's obviously not how gravity works. This is why I'm currently a fan of the theory that gravity is a curvature in spacetime, the same way a bowling ball sitting on a matress curves the surface of it. Just as the bowling ball bends a two-dimensional surface into a third dimension, the presence of a large mass in space bends three-dimensional space into a fourth. The curved-space deal seems to be a good explanation of how gravity can exert its force while passing right through entire planets.

[RainDreamer]

Gravity is a curvature of spacetime. The further away you are from your mass, the curve is more shallow, hence less attraction.

Here is a video that has been posted around here a while ago, but I think it is worth bringing back:

It is difficult to visualize that in a 3D form though.

[GeneralVeers]

Not difficult at all. Go to YouTube and watch a video on gravitational lensing (ideally one of those where they show a black hole passing in front of something and warping the scenery around it!) That's what 3D space looks like when it's bent out of shape into four dimensions. In the same way that your brain looks at a two-dimensional picture of a cube and easily sees a three-dimensional cube, the three-dimensional representation we can see of four-dimensional space is pretty boring.

[Skyler4856]

So past Jupiter (like @Ralathon mentioned) each photon is carrying less energy? That would means for me it is getting weaker.

It's more of a quirk in geometry than anything. Besides, where would the lost energy go?