Acting as a 'natural telescope' in space, the gravity of the extremely massive foreground galaxy cluster
MACS J2129-0741 magnifies, brightens, and distorts the far-distant background galaxy
MACS2129-1 [top box]. The middle box is a blown-up view of the gravitationally lensed galaxy. The bottom box is a reconstructed image, based on modeling, that shows what the galaxy would look like if the galaxy cluster were not present. The galaxy appears red because it's so distant that its light is shifted into the red part of the spectrum.