Caption

Hubble Space Telescope image and of a galaxy cluster about 4.6 billion light years from Earth. The four bright arcs (three at top right and one at lower left) are light from another galaxy, named the Sunburst Arc. It is almost 11 billion light-years from Earth. The light from the Sunburst Arc is being distorted into multiple images by gravitational lensing. The Sunburst Arc is among the brightest lensed galaxies known and its image is visible at least 12 times within the four arcs. The arc at lower left is partially obscured by a bright foreground star, which is located in the Milky Way. Gravitational lensing occurs when light from a distant source is bent by the curvature of spacetime due to matter between the light source and the observer. The bending of light by gravity was predicted by Albert Einstein in his general theory of relativity. In 1937, the astronomer Fritz Zwicky suggested galaxy clusters could act as gravitational lenses.