Photon Ring Horizontal (IMAGE) Institute for Advanced Study Caption The image of a black hole has a bright ring of emission surrounding a "shadow" cast by the black hole. This ring is composed of a stack of increasingly sharp subrings that correspond to the number of orbits that photons took around the black hole before reaching the observer. Credit George Wong (UIUC) and Michael Johnson (CfA) Usage Restrictions None License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.