M3 Globular ClusterThe globular cluster M3 is notable for containing more variable stars than any other known cluster. The brightness of a variable star fluctuates with time. Credits: NASA, ESA, STScI and A. Sarajedini (University of Florida) Download Share Tags Hubble Space TelescopeImage CreditNASA, ESA, STScI and A. Sarajedini (University of Florida)Size640x626px