Friday, November 27, 2015

gravity - Does light have mass as it is attracted through gravitational force?



I have heard that no one escape from the intense gravitational field of a black hole (obviously that's why it is black). And gravitational force is due to the mass having the body, no mass no gravity, as $$F=GMm/r^2$$ Putting $0$ in one of the two bodies' masses, gives no gravitational force. But light cannot escape from black hole due to its strong gravity, does that mean that light has mass? please correct me.




Answer



Light does not have mass and Newton's theory of gravity doesn't work here. Any massive object, like the Sun, locally deforms the flat fabric of spacetime into a curved one. Light bends because it has to follow the geodesic (shortest distance between two points in a curved space) as Einstein taught us in his general theory of relativity.


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