Gravitational lens

Light bending by mass between source and observer

A gravitational lens is matter, such as a cluster of galaxies or a point particle, in sufficient quantity and density to bend light noticeably from a distant source as it travels toward an observer. The amount of gravitational lensing is described by Albert Einstein's general theory of relativity. If light is treated as corpuscles travelling at the speed of light, Newtonian physics also predicts the bending of light, but only half of that predicted by general relativity.

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