This image shows just a portion of Messier M55. The smaller, ground-based image (lower left) taken by the Digital Sky Survey illustrates an area of Messier 55 that Hubble observed. The globular cluster is about 20,000 light-years away and is about 100 light-years in diameter. It contains an estimated 100,000 stars with 55 variable stars whose brightness changes. The cluster as a whole appears spherical because the stars’ intense gravitational attraction pulls them together.
Image Credits: NASA / ESA / A. Sarajedini (Florida Atlantic University) / M. Libralato (STScI, ESA, JWST) / and Digital Sky Survey
Image Processing: Gladys Kober