Spiral structure in the Pinwheel Galaxy (IMAGE) Royal Astronomical Society Caption Spiral structure in the Pinwheel Galaxy (Messier 101), as observed by the Hubble Space Telescope. Credit NASA, ESA, CXC, SSC, and STScI 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.