If you put 2 apples a billion lightyears apart in a void, would they eventually touch from gravity alone?
>>16945430Yes.
>>16945430no they would decay and stop being apples before they reached each other
>>16945430>>16945433Anything within the parameters of the universe is possible given enough time. It's the reason you guys exist.
>>16945430I think, yea. On a very large but finite timescale.>>16945438We're talking about idealized apples.
>>16945430Were they toffee apples? I supposed you could crystallize them for billions of years. Or do that trick with collapsing the wave, and in some extreme parts of the universe it takes longer for it to flip.
>>16945430Is this void a part of an expanding universe? If so, the rate of expansion may far exceed the gravitation of the apples
Nope. People who say yes think it's so because gravity has "infinite range", but that's only one part of the story. It's the midwito response. It's true that it doesn't technically terminate, but any spacetime where christoffel symbols aren't zero will leak energy, and any "force" of the apples working against each other will be counteracted, as any acceleration will leak.There's no energy conservation in GR (best model of gravity).And that's not accounting for spacetime expansion ie. non zero cosmological constantSo, no, they would not touch.>>16945440>>16945433>>16945443arrogant midwit>>16945520high tier midwit (reddit phd)
>>16945430Great question — and the answer is **yes**, in principle, though with some important caveats.Two apples placed at rest in an otherwise empty, static universe would gravitationally attract each other and eventually collide, no matter how far apart they are. Gravity has infinite range and there's no threshold distance below which it "turns off." The force would be extraordinarily tiny at a billion light-years, but in a perfect void with nothing else acting on them, even that infinitesimal tug would slowly accelerate them toward each other.**How long would it take?** An absurdly long time — far longer than the current age of the universe. At a billion light-years of separation, the gravitational acceleration between two ~200g apples is something like 10-55 m/s2. The fall time would be on the order of 1030 years or more (the universe is only about 1010 years old).**The real-world wrinkle: expansion of spacetime.** In our actual universe, space itself is expanding — and at cosmological distances, that expansion outpaces the gravitational pull between small masses. A billion light-years is well beyond the scale where the apples' mutual gravity could overcome the Hubble flow. So in a realistic cosmological setting, the apples would actually drift *further* apart over time.So the answer splits in two:In a **static, empty universe** (the idealized thought experiment) — yes, they'd eventually meet. Gravity always wins given infinite time and no opposing forces.In **our actual expanding universe** — no. At that distance, cosmic expansion dominates, and two apples don't have nearly enough mass to form a gravitationally bound system.It's a nice illustration of how gravity is simultaneously the weakest force and the most persistent one — and of how the cosmological context can completely change the outcome.
>>16945555As someone who initially said yes, I hereby concede and accept that you are a better person, and lover, than myself.
>>16945575GPTslop
>>16945555You don't even know the words you're using
>>16945430acceleration = velocity increases near c
we dont understand quantum gravity but in all likelihood theres a minimum discrete value for gravitational force (one "graviton") like there is for all the other forces and this scenario would be far lower than that, so no.
>>16945555Just because they swirl about eachother for a little while, doesn't mean they won't touch.
>>16945430>>16945555Energy is only not conserved due to expansion. Photons lose energy over time as space expands. So you ARE accounting for spacetime expansion already.In a non-expanding universe energy is conserved because the energy of the photon is constant. So the question depends entirely on the rate of expansion. If it’s a true static “void” with just the two apples, not expanding or with a very low rate of expansion, eventually they will interact. There some math we could do to see how rapidly spacetime would need to expand to redshift a photon into nothingness over a few billion light years but I’ll let someone else do that.
>>16945682The fact that photons have no mass means mass can't be discrete. Nothing is ever really discrete anyways.
>>16945555>There's no energy conservation in GR (best model of gravity).
