Gravity does affect light and other electromagnetic waves, and one of the most significant effects is gravitational lensing. Gravitational lensing occurs when the path of light or electromagnetic waves is bent by the gravitational field of a massive object, such as a star or a galaxy. This bending of light can cause the light to be redirected or focused, leading to interesting observational effects.
One famous example of gravitational lensing is the phenomenon known as Einstein's Cross. It involves a distant quasar—a highly luminous object powered by an active galactic nucleus—and a foreground galaxy acting as the gravitational lens. The gravitational field of the foreground galaxy bends the path of the quasar's light, resulting in four distinct images of the quasar appearing around the galaxy. These four images form a cross-like pattern, hence the name Einstein's Cross.
Gravitational lensing can also produce an "Einstein ring" when the light from a distant object, such as a galaxy, is lensed by a massive object directly in front of it. The bending of light creates a circular or elliptical shape around the massive object, resembling a ring. This phenomenon has been observed and studied extensively, providing valuable insights into the distribution of matter and the effects of gravity in the universe.
These examples demonstrate how gravity can influence the path of light and electromagnetic waves, resulting in observable distortions and redirections. Gravitational lensing has become an important tool in astrophysics for studying the properties of distant objects and testing our understanding of gravity and the structure of the universe.