I have read in a book and on the internet that the graviton is the particle which causes gravity, and not even light can escape gravity.
Suppose our Sun has turned into a black hole. The black hole will still have the same gravitational effect on other matter as the Sun.
Nothing can escape from a black hole, but a black hole still has a gravitational effect. How is this possible? Won't the black hole stop the gravitons and lose its gravitational effect?
To start with, gravitons are in the realm of quantum mechanics, and gravity has not yet been definitively quantized .
If one supposes that the classical gravitational field , in an effective gravitational quantization, would behave as photons in field theory, then the analogue is the electric field. The electric field of a charged particle does not emit photons, as it would lose energy/mass. It emits at a limit virtual photons . I.e. a test charge and the charge under measurement exchange virtual photons , which replace the concept of the classical field lines between the two charged particles.
Virtual photons have the quantum numbers of a photon but are off mass shell.They are a mathematical entity useful in calculating interactions.
In a similar manner a classical gravitational field would be exchanging virtual gravitons with a test mass, as it is falling towards the singularity.
