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What does he mean by "gravity responds to all kinds of energy"? What about photons?
by madengr 10y ago
What does he mean by "gravity responds to all kinds of energy"? What about photons?
- egjerlow 10y agoyes, those too. Light is influenced by gravitational fields!
- de_Selby 10y agoIs it not more a case of space-time being influenced rather than light?
- madengr 10y agoYes, I would think. Gravity warps space, and light just follows a line in space, which is a curve in space-time. But since gravity can affect light, does light (energy) affect gravity?
- auntienomen 10y agoYes. The gravitational field couples to any energy; it doesn't care what the source is. Light carries energy, so the gravitational field responds to it.
- OscarCunningham 10y agoYeah, in physics if A affects B then B always affects A. This idea was first formalised as Newton's Third Law.
- egjerlow 10y agoMore formally, a photon field contributes to the so-called stress-energy tensor,which acts as the 'source' of gravity in the Einstein equations, thus affecting gravity, as you say.
- XaspR8d 10y agoYou might be interested to read about the kugelblitz: > In theoretical physics, a kugelblitz is a concentration of light so intense that it forms an event horizon and becomes self-trapped: according to general relativity, if enough radiation is aimed into a region, the concentration of energy can warp spacetime enough for the region to become a black hole. https://en.wikipedia.org/wiki/Kugelblitz_(astrophysics) https://en.wikipedia.org/wiki/Kugelblitz_(astrophysics)