4 ms·
This is what I wanted to know too. Speaking as a non-physicist and a layman, that's almost the first conundrum that occurs to you when reading about black holes
by Santosh83 9y ago
This is what I wanted to know too. Speaking as a non-physicist and a layman, that's almost the first conundrum that occurs to you when reading about black holes from popular science literature. How is it that gravitons can seemingly be exchanged by the pair of masses for any body to feel the pull of a black hole?
I still don't quite get "the gravitational field at the border, within our observable universe, is intense enough to whip itself up into a self-maintaining recursive but sustainable loop" (especially the self-maintaining, recursive part. How?), but I guess one would need a good understanding of GR to go beyond this level?
- rotorblade 9y agoSince black-holes interact gravitationally with other particles, there must be a mediation of a graviton between them (assuming quantum properties of gravity). However, force mediation is different from a physical particle escaping one object than interacting with another (e.g. physical graviton escaping a BH, interacting with an other particle). That is why we have the concept of virtual particles [0]: "[...] the electromagnetic repulsion or attraction between two charges—can be thought of as due to the exchange of many virtual photons between the charges." so when the electromagnetic force mediation takes place, it exchanges virtual photons, and this is different from an object exchanging physical photons with another (which we would more think of as one object shining (if the photon is in the visible spectrum) on another). How a virtual graviton would interact between BHs and other particles are up to any suggested theory for quantum gravity to explain. [0] https://en.wikipedia.org/wiki/Virtual_particle https://en.wikipedia.org/wiki/Virtual_particle
- Santosh83 9y agoThanks. That makes it somewhat clearer. Also including both links below as they are relevant to this misconception: http://math.ucr.edu/home/baez/physics/Relativity/BlackHoles/black_gravity.html http://math.ucr.edu/home/baez/physics/Relativity/BlackHoles/... https://www.quora.com/in/If-both-the-photon-and-the-graviton-are-massless-how-do-we-explain-that-the-photon-cannot-escape-a-black-hole-and-the-graviton https://www.quora.com/in/If-both-the-photon-and-the-graviton...
- qubex 9y agoI’m not a physicist but I have a background in applied mathematics. What I am trying to describe is the inherent nonlinearity of general relativity, wherein compound solutions cannot be obtained simply summing up or overlaying simpler situations: the gravity filed itself generates more gravity, so it can recursively reach and sustain a critical value.
- Simon_says 9y agoBlack holes also evaporate. What’s happening here to make the field get smaller and ultimately disperse if the field is self-sustaining?