Einstein Cross

Facts for Prelims

Einstein Cross

News: Astronomers have discovered a rare example of an “Einstein cross,” a phenomenon predicted by Albert Einstein in 1915.

What is Einstein Cross?
• An Einstein cross is a rare phenomenon that occurs when the light from a very distant object, such as a quasar, is bent and split into four images by the gravity of a massive foreground object, such as a galaxy. This creates a cross-shaped pattern of four bright spots around the center of the galaxy.
• The name comes from Albert Einstein, who predicted this effect in his theory of general relativity. Significance:
• An Einstein cross is not only a beautiful sight, but also a useful tool for astronomers to study the distant universe. By measuring the brightness and spectra of the four images, they can learn more about the properties of the quasar, the galaxy, and the intervening space. They can also test and refine the predictions of general relativity and cosmology.