Local Group

The Local Group is a group of galaxies that includes our own Milky Way, where Earth is located. It has two main parts shaped like a dumbbell. One part is centered on the Milky Way and its smaller galaxies. The other part is centered on the Andromeda Galaxy and its smaller galaxies. These two parts are moving toward each other and are about 800 kiloparsecs apart.

The Local Group has a total mass of about 2×10¹² solar masses and a diameter of about 5.11 megaparsecs. It is part of a larger structure called the Local Volume, which belongs to the Virgo Supercluster. The exact number of galaxies in the Local Group is not fully known because the bright Milky Way blocks some views, but we currently know of 134 galaxies within 1 megaparsec of the center.

The two largest galaxies in the Local Group are the Andromeda Galaxy and the Milky Way. Both are spiral galaxies and each has many smaller galaxies orbiting around them. The third-largest galaxy is the Triangulum Galaxy. Together, these galaxies and their companions make up the Local Group, a fascinating part of our universe’s structure.

History

The term "The Local Group" was first used by Edwin Hubble in his book in 1936. He called it a small group of galaxies that are alone in space. Hubble listed several galaxies in this group. These include the Andromeda Galaxy, the Milky Way where our Earth is, and the Triangulum Galaxy. He also named smaller galaxies like the Large Magellanic Cloud and the Small Magellanic Cloud. He thought IC 10 might also be part of this group.

Component galaxies

The Local Group is a group of galaxies that includes our own Milky Way. It looks like a dumbbell, with the Milky Way and its smaller galaxies on one side, and the Andromeda Galaxy and its smaller galaxies on the other. These two big groups of galaxies are moving closer to each other.

Structure

The Local Group is made up of the Milky Way, where our Earth is located, and the Andromeda Galaxy, along with their smaller companion galaxies. These galaxies are arranged in a shape like a dumbbell, with the Milky Way and Andromeda on each end.

Some interesting features include the Magellanic Stream, a trail of gas being pulled away from small galaxies near the Milky Way, and the Monoceros Ring, a ring of stars that may have come from another small galaxy. There are also other streams of stars, like the Virgo Stream and Helmi Stream, which are remains of smaller galaxies that have merged with larger ones.

Future

The galaxies in the Local Group will slowly come together because of their gravity. Over many billions of years, they will form one big galaxy. The biggest event will be when the Andromeda Galaxy and our Milky Way merge. Scientists wonder what the new galaxy will look like. Some think it will be round, while others think it might keep some of its spiral arms for a while before changing.

Location

Main article: Laniakea Supercluster

We live in the Milky Way galaxy. The Milky Way is part of a group of galaxies called the Local Group. This group looks like two balls connected together, shaped like a "dumbbell." One ball has the Milky Way and its small galaxies. The other ball has the Andromeda Galaxy and its small galaxies. These two groups are moving slowly toward each other.