Andromeda Galaxy

space · galaxies · nearest neighbor

Our cosmic neighbor. Andromeda is the nearest major galaxy to the Milky Way, sitting about 2.5 million light-years away. That might sound far, but in space terms, it's practically our next-door neighbor.

Truly enormous. Andromeda stretches about 152,000 light-years across, making it one of the largest galaxies we know of. If you could see its entire size from Earth, it would cover an area of sky six times wider than the full moon.

Spiral with a bar. Andromeda is a barred spiral galaxy, which means it has a straight bar of stars running through its middle with spiral arms curling out from the ends, like a cosmic pinwheel.

Many names. Scientists call it Messier 31 or M31 for short because it's the 31st object on a famous list of fuzzy things in the sky. It's also known as NGC 224 in another catalog.

Named after mythology. The galaxy gets its name from the constellation Andromeda, which itself is named after a princess in ancient Greek stories who was married to the hero Perseus.