Most galaxies have a single nucleus — does this galaxy have four? The strange answer leads astronomers to conclude that the nucleus of the surrounding galaxy is not even visible in this image . The central cloverleaf is rather light emitted from a background quasar . The gravitational field of the visible foreground galaxy breaks light from this distant quasar into four distinct images. The quasar must be properly aligned behind the center of a massive galaxy for a mirage like this to be evident. The general effect is known as gravitational lensing , and this specific case is known as the Einstein Cross . Stranger still, the images of the Einstein Cross vary in relative brightness, enhanced occasionally by the additional gravitational microlensing effect of specific stars in the foreground galaxy. Almost Hyperspace: Random APOD Generator Image Credit & License: NSF , NOIRLab , AURA , WIYN ; Processing: J. Rhoads ( Arizona State U. ) et al. https://science.nasa.gov/image-article/apod-2026-january-4-the-einstein-cross-gravitational-lens/