lens, gravitational

Object in space which, by its gravitational field, bends light in a similar way to a spectacle lens. As a result of this, one object, such as a quasar, can appear as multiple images. A gravitational lens also produces a magnifying effect. Numerous examples are now known of such multiple imaging. Images of quasars and galaxies are also stretched into arcs by gravitational lenses.

See gravitational lensing.