ComputerScience. Physics. QuantumMechanics. Physics. Physics - spotlighting exceptional research. TONE SCIENCE. Gravitational lens. A light source passes behind a gravitational lens (point mass placed in the center of the image).
The aqua circle is the light source as it would be seen if there was no lens, white spots are the multiple images (or Einstein ring) of the source. A gravitational lens is a distribution of matter (such as a cluster of galaxies) between a distant light source and an observer, that is capable of bending the light from the source as the light travels towards the observer. This effect is known as gravitational lensing, and the amount of bending is one of the predictions of Albert Einstein's general theory of relativity.[1][2] (Classical physics also predicts the bending of light, but only half that predicted by general relativity.[3]) Gravitational microlensing. Gravitational microlensing is an astronomical phenomenon due to the gravitational lens effect.
It can be used to detect objects ranging from the mass of a planet to the mass of a star, regardless of the light they emit. Typically, astronomers can only detect bright objects that emit lots of light (stars) or large objects that block background light (clouds of gas and dust). These objects make up only a tiny fraction of the mass of a galaxy.