About 100 years after astronomer Edwin Hubble's discovered the "magnificent" spiral nebula, the Hubble Space Telescope and NASA scientists have produced the most comprehensive survey of the Andromeda galaxy, or Messier 31. The Andromeda galaxy is approximately 2.5 million light-years away from the Milky Way.

The Andromeda galaxy is a colossal marvel in our sky, hosting over 1 trillion stars. Now, astronomers have used the Hubble Space Telescope to capture hundreds of detailed images of our vast galactic neighbor, creating the largest-ever photomosaic of the galaxy. It took over 10 years to create.

In the years following the launch of NASA's Hubble Space Telescope, astronomers have tallied over 1 trillion galaxies in the universe. But only one galaxy stands out as the most important nearby stellar island to our Milky Way—the magnificent Andromeda galaxy (Messier 31).