In the largest NASA Hubble Space Telescope image ever assembled, this sweeping bird’s-eye view of a portion of the Andromeda galaxy (M31) is the sharpest large composite image ever taken of our galactic next-door neighbor. Although the galaxy is over 2 million light-years away, the Hubble Space Telescope is powerful enough to resolve individual stars in a 61,000-light-year-long stretch of the galaxy’s pancake-shaped disk.
It's like photographing a beach and resolving individual grains of sand. And there are lots of stars in this sweeping view – over 100 million! Some of these can be seen embedded in the disk as thousands of star clusters.
This ambitious photographic cartography of the Andromeda galaxy represents a new benchmark for precision studies of the large spiral galaxies that dominate the universe's population of over 100 billion galaxies. Never before have astronomers been able to see the individual stars inside an external spiral galaxy over such a large contiguous area. As most of the stars in the universe live inside such majestic star cities, this is the first data that reveals star populations in context to their home galaxy.
The video below explains how this what accomplished and shows some highlights from the photo. We recommend you take a minute to watch it without distractions.
It is magnificent.
The Hubble Space Telescope is a project of international cooperation between NASA and the European Space Agency. NASA's Goddard Space Flight Center in Greenbelt, Maryland, manages the telescope. The Space Telescope Science Institute (STScI) in Baltimore conducts Hubble science operations. STScI is operated for NASA by the Association of Universities for Research in Astronomy, Inc., in Washington.
Image Credit: NASA, ESA, J. Dalcanton, B.F. Williams, and L.C. Johnson (U. of Washington), the Panchromatic Hubble Andromeda Treasury (PHAT) team, and R. Gendler