Gravitational lensing of the distant SPT0418-47 galaxy (schematic)

This schematic animation shows how light from a distant galaxy is distorted by the gravitational effects of a foreground galaxy, which acts like a lens and makes the distant source appear distorted, but magnified, forming characteristic rings of light, known as Einstein rings. This effect has allowed astronomers to see the distant galaxy SPT0418-47 (which appears as a golden ring in the ALMA images) in finer detail than would have been possible otherwise. 

The foreground galaxy is not visible in the ALMA images of SPT0418-47 because it is too faint at the wavelengths used. The blue colour used in this schematic to represent this foreground galaxy is artificial.