The Andromeda Galaxy

The Andromeda Galaxy

The Andromeda Galaxy (M31) is the closest large galaxy to the Milky Way and is the most distant object in the sky that you can see with your unaided eye unaided from the Earth. At a distance of about 2.5 million light years, the Andromeda galaxy (also known as NGC 224 and M31).

The Andromeda Galaxy is approaching the Milky Way at approximately 140 kilometers per second. In approximately 4.5 billion years the Andromeda Galaxy and the Milky Way are expected to collide. Predictions are that our Sun could one day move and become a part of the Andromeda Galaxy.


Located just to the north of the constellation Andromeda, the galaxy appears as a long, hazy patch in the sky. In the30inch it its shape will be clearly revealed its shape

The extent of the galaxy is large; it stretches to about six times as large the full moon. A spiral galaxy like the Milky Way, Andromeda contains a concentrated bulge of matter in the middle, surrounded by a disk of gas, dust, and stars 260,000 light-years long, more than 2.5 times as long as the Milky Way. The spiral arms stretch out from the core to a diameter of between 100,000 and 220,000 light-years.

Though Andromeda contains approximately a trillion stars to the quarter to half a billion in the Milky Way, our galaxy is actually more massive, because it is thought to contain more dark matter.

As with most, if not all, similar galaxies, Andromeda owes its shape to a supermassive black hole somewhere within its core. Recent research, however, indicates that Andromeda’s core arrangement is unusual. Andromeda appears to have a cluster of numerous black holes – one recent survey counted 26 of them.  Current belief is that about 5 to 9 million years ago small galaxies collided and created Andromeda.

Andromeda Galaxy Facts:


  • The Andromeda Galaxy gets its name from the mythological princess Andromeda
  • The Andromeda Galaxy is bigger than the Milky Way Galaxy.
  • During the 17th century, astronomers thought that Andromeda was a portion of the Milky Way.
  • Because of the similarities, observations of the Andromeda are how astronomers make and test assumptions about the Milky Way.
  • The Andromeda Galaxy and the Milky Way Galaxy are being drawn closer and closer together.
  • Andromeda is 260,000 light years long.
  • Although the Milky Way has more mass, Andromeda is considered to be the largest galaxy.
  • The Andromeda Galaxy is a part of a cluster of galaxies called the Local Group.
  • The Milky Way will merge with Andromeda in roughly 5 billion years.
  • The Andromeda Galaxy is located inside of the Andromeda Constellation which can be seen in the northern sky.

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