Local Group

The Local Group is the galaxy group that includes the Milky Way, where our Earth is located. It consists of two collections of galaxies shaped like a "dumbbell". One side has the Milky Way and its smaller galaxies, while the other side has the Andromeda Galaxy and its smaller galaxies. These two collections are about 800 kiloparsecs apart and are moving toward each other.

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 the larger Local Volume, which is inside the Virgo Supercluster. The exact number of galaxies in the Local Group is not known because the bright Milky Way hides some of them. However, scientists have identified around 134 galaxies within 1 megaparsec of the center. Most of these are small dwarf galaxies.

The two biggest galaxies in the Local Group are the Andromeda Galaxy and the Milky Way. Both are spiral galaxies with masses of about 10¹² solar masses each. They each have their own systems of smaller galaxies orbiting around them. The third-largest galaxy is the Triangulum Galaxy, which is smaller than the other two but still quite big. There are many other smaller galaxies in the Local Group, each with its own interesting features and histories.

History

The term "The Local Group" was introduced by Edwin Hubble in his 1936 book The Realm of the Nebulae. In this book, Hubble described the Local Group as a small collection of galaxies that are isolated in space. He listed several galaxies that belong to this group, including M31, the Milky Way, M33, the Large Magellanic Cloud, the Small Magellanic Cloud, M32, NGC 205, NGC 6822, NGC 185, IC 1613, and NGC 147. He also mentioned that IC 10 might be part of the Local Group.

Component galaxies

The Local Group is a collection of galaxies that includes our own galaxy, the Milky Way. It is shaped like a dumbbell, with the Milky Way and its smaller galaxies forming one side, and the Andromeda Galaxy and its smaller galaxies forming the other side. These two groups of galaxies are moving towards each other.

Structure

The Local Group has some interesting features called streams. These are long, thin collections of stars or gas that have been pulled away from smaller galaxies by the gravity of larger ones. For example, the Magellanic Stream is a stream of gas being pulled from the Magellanic Clouds by the Milky Way. The Monoceros Ring is a ring of stars around the Milky Way that may have come from a small galaxy called the Canis Major Dwarf Galaxy. Other streams, like the Virgo Stream and Helmi Stream, are also formed from smaller galaxies that have been influenced by larger ones.

Future

The galaxies in the Local Group, including the Milky Way and the Andromeda Galaxy, are moving towards each other and will eventually merge into a single large galaxy over many billions of years. Scientists discuss different ideas about what this new galaxy might look like after the merger, with some thinking it will become a round elliptical galaxy and others suggesting it might keep some spiral features or become a different type of galaxy altogether.

Location

Main article: Laniakea Supercluster

The Local Group is a collection of galaxies that includes the Milky Way, where our Earth is located. It has a special shape 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 side. These two groups of galaxies are moving towards each other.