3 ms·
What is the currently accepted answer to the question, "what is gravity"?
by newsbinator 7y ago
What is the currently accepted answer to the question, "what is gravity"?
- tus88 7y agoCurvature in spacetime.
- ralusek 7y agoThat which maketh the apple bonk the skull most uninvitedly.
- polynomial 7y agoApple bonkers?
- dvh 7y agoGravity is one of the essential forces in nature. If you want to explain it in simpler terms it is not possible because gravity is the simpler thing. You can use gravity to explain other things, but you cannot use other things to explain gravity.
- ThemalSpan 7y agoMaybe. Maybe not. https://en.wikipedia.org/wiki/Entropic_gravity https://en.wikipedia.org/wiki/Entropic_gravity
- pmorais 7y agoThat’s not really true. The other 3 “fundamental” forces are irreducible yet still entirely explained by the standard model.
- gpderetta 7y agoWell, gravity is similarly explained by general relativity.
- narag 7y agoEinstein believed gravity isn't really a force in the same sense as the other three fundamental forces, but a property of space-time. That seems to be a problem because it causes some kind of "incompatibilty" with the others. Trying to reconcile those, efforts has been made to create quantum gravity theories, that view space itself as quantized and in this direction you find strings and quantum loop gravity. Disclaimer: I'm no expert, just parroting what I found in Wikipedia.
- gpderetta 7y agoIANAP either but as far as I understand the incompatibility is not on wether gravity is a force or not (that's just a way to interpret the equations). The issue is that all attempts to quantize gravity have failed so far (due to the specific mathematical properties of the gravitational field) and QFT would require gravity to be quantized to interact with other quantum fields.
- NeedMoreTea 7y agoThe dent in the rubber sheet that the earth currently sits on - hence the whole curvature in spacetime thing. As far as I know no one has figured out or found gravitons yet, so it's just a theory. Which I assume means there should be a few gravity-deniers out there to give themselves a break from global heating denial. :)
- timonoko 7y agoIt is an illusion. You are floating freely in the space, but massive mass near-by is causing curvature in space-time. In other words: Time goes more slowly in your shoes, because they are closer to the mass. This causes any movement to be circular movement, which is pressing you to the near-by mass, which you experience as "gravity".
- majke 7y agoWow, what an excellent way of phrasing it. Give me more. Why "any movement is circular"?
- Firadeoclus 7y agoIt seems to me that, as soon as there is mass in the universe which curves space-time, all paths of movement are closed. To a first approximation, for anything close to a single large mass that means an elliptical path. That assumes, of course, that an instantaneous "path of movement" is something that is even worth considering, given that it ignores the time dimension and the fact that all those other objects aren't remaining in a static configuration around the object whose path we are considering.
- TeMPOraL 7y agoI would think that parabolic trajectories only close in infinity, and hyperbolic not even there? Or both close only in infinity? The math on that is currently out of my brain's cache.
- rbanffy 7y agoThey all close. Worst case is they'll get longer and longer as the universe expands and the objects will never be able to complete them and come back for a second lap.
- ErotemeObelus 7y agoIf you're not going in a straight line then your motion has a radius. This is why people lost in the woods go in circles, because their walk (unless a compass is correcting you) always has a slight curve.
- Grimm665 7y agoThis video by Vsauce really put it in a way that made it stick for me. https://www.youtube.com/watch?v=Xc4xYacTu-E https://www.youtube.com/watch?v=Xc4xYacTu-E