Galaxy group facts for kids
A galaxy group is a collection of galaxies that are held together by gravity. Think of them like cosmic neighborhoods! These groups usually have fewer than 50 galaxies. When you find even bigger collections of galaxies, they are called galaxy clusters or superclusters. Our very own galaxy, the Milky Way, is part of a galaxy group called the Local Group. It has more than 40 galaxies in it!
What is a Galaxy Group?
Galaxy groups are the smallest types of galaxy collections. They are like small towns in the universe, while galaxy clusters are more like big cities. The galaxies in a group are close enough to each other that their gravity pulls them together. This keeps them from drifting away into space.
Our Cosmic Neighborhood: The Local Group
The Milky Way galaxy, where our Earth and Sun live, is part of a galaxy group called the Local Group. This group is home to over 40 different galaxies. The two biggest galaxies in our Local Group are the Milky Way and the Andromeda Galaxy. They are both spiral galaxies, meaning they have a shape like a giant pinwheel. Other galaxies in the Local Group are smaller, like dwarf galaxies.
How Big Are They?
Galaxy groups are quite large, even though they are the smallest type of galaxy collection. They can stretch across 4 to 8 million light-years of space. To give you an idea, one light-year is how far light travels in one year, which is a huge distance!
These groups are also incredibly heavy. They can weigh as much as 10 trillion (10,000,000,000,000) times the mass of our Sun! This huge weight comes from all the stars, gas, dust, and even mysterious dark matter inside the galaxies and between them. Sometimes, even larger and heavier collections of galaxies are still called galaxy groups, but usually, they are smaller than galaxy clusters.
