Source: wikibot/einstein-radius
= Einstein radius
{wiki=Einstein_radius}
The Einstein radius is a concept from gravitational lensing, which is the bending of light caused by the gravitational field of massive objects, such as galaxies or galaxy clusters. When a light source (like a distant star or galaxy) is perfectly aligned with a massive foreground object (the lens), the light from the source can be bent around the lens, creating multiple images or a ring-like structure known as an "Einstein ring.