Defining a galaxy sounds so simple. We all know what a galaxy is, right? Well, not really. Surprisingly, there is no universally agreed upon definition and the ones generally bandied around leave a ...

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 ...

Spiral galaxies are twisted collections of stars and gas that often have beautiful shapes and are made up of hot young stars. Most of the galaxies that scientists have discovered so far are spiral ...