Milky Way and Andromeda Galaxies

Presentation by Edgar Saldivar and Tanner Bauknight


Throughout our presentation, you will learn about the Milky Way Galaxy and our closest galaxy neighbor Andromeda Galaxy. You will also learn the similarities and differences between the Milky Way Galaxy and the Andromeda Galaxy

Milky Way Galaxy

The Milky Way Galaxy is a disc that is about 120,000 light years across. The Milky Way is warped because the Large and Small Magellanic clouds have been pulling on the on the dark matter in the Milky Way. There are 200-400 billion stars in our galaxy, but because of the large size you can only see so many. The Milky Way houses the Solar System and Earth. The galactic bulge (the heart of galaxy) is in the center of the galaxy, and is full of gas, dust, and stars. The Milky Way does not sit still, but is constantly rotating. It travels at 515,000 miles per hour. Even at this rate, it would take 230 million years for the solar system to go all the way around it. Right in the middle of the galaxy, there is a gigantic black hole that is billions of times more massive than the Sun. There is also a spherical halo that surrounds the galaxy. Even though it stretches for hundreds of thousands of light years, it only has 2% the stars in the disk. Is estimated that the black matter in the galaxy makes up 90% of the mass.

Andromeda Galaxy

The Andromeda Galaxy is the closest neighbor to us. It is located just north of the constellation of the same name (Andromeda). The center of the galaxy has dust, gas, and stars, and is 260,000 light years across. It is more than 2.5 times bigger than the Milky Way, and it contains a trillion stars. This galaxy is 2.5 million light years away, even though it looks like a full moon and half as wide. Unfortunately, Andromeda will collide with us in about 5 billion years, since it travels at 70 miles per second. In the 1920's it was believed that the Milky Way was the entire Universe, but the discovery of Andromeda opened up the debate between astronomers. Simon Marius, a german astronomer, discovered and described Andromeda in 1612.

Differences between the two galactic bodies.

Milky Way Galaxy is a galaxy that has arms, while Andromeda does not have galactic arms. Our Sun is located in one of Milky Way's arms. Our galactic neighborhood is 100,000 light years across, while Andromeda is about 260,000 light years across. Milky Way has 200-400 billion stars, while Andromeda has about 1 trillion. Even though Andromeda is much bigger, Milky Way Galaxy is more massive than our close neighbor because our galaxy contains more dark matter.


Milky Way Galaxy and Andromeda Galaxy are both spiral kinds of galaxy. Both the Milky Way and Andromeda Galaxies are found in the Local Group, a group of 54 galaxies. These galaxies were formed roughly at the same time, which is about 13.5 billions years ago in the creation of the Universe. They are both going to collide with each other in about 3 billion years, since they are approaching each other at a speed of 200 kilometers per second.


We hope that you learned about this discovery that opened more doors to exploration. This has not been out for very long, and astronomers are determined to find more information about it. Even though we do not know a lot about Andromeda, we know that it is similar to the Milky Way, but they have their differences as well. Hopefully we will know more about this subject, and we could truly compare both of the galaxies.