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Concepts in astronomyGalaxies

Galaxy

Adapted from Wikipedia · Explorer experience

A stunning view of the Pinwheel Galaxy, a beautiful spiral galaxy located in the constellation Ursa Major, captured by the Hubble Space Telescope.

What is a Galaxy?

A galaxy is a huge, beautiful family of stars, gas, dust, and something called dark matter. They are all held together by gravity, which is the same force that keeps you on the ground. Our own home, the Solar System, lives inside a big galaxy called the Milky Way.

Different Kinds of Galaxies

Galaxies come in many shapes and sizes. Some are small and round, called dwarfs. Others are very large, with up to one hundred trillion stars! We usually sort them into three main types:

  • Spiral galaxies look like spinning pinwheels. The Milky Way is one of these. They have bright arms made of young stars.
  • Elliptical galaxies are smooth and round, like fluffy balls. They mostly have older stars.
  • Irregular galaxies don’t fit into the other groups. They look jumbled and messy.

Fun Facts About Galaxies

  • The word “galaxy” comes from an old Greek word meaning “milky,” because of the milky band of light we see in our sky—the Milky Way.
  • Scientists think there are between 200 billion and 2 trillion galaxies in the whole universe!
  • Many galaxies have huge black holes right in the middle. These are very heavy places where nothing, not even light, can escape.

Where Galaxies Live

Galaxies are rarely alone. They often live in groups or clusters, held together by gravity. Our Milky Way is part of a group called the Local Group, which includes the bright Andromeda Galaxy and many smaller ones.

Galaxies can even crash into each other over millions of years, changing their shapes. Far in the future, the Milky Way might meet and join with Andromeda Galaxy!

Images

A stunning view of the barred spiral galaxy NGC 1300, showcasing its intricate spiral arms and star clusters as captured by the Hubble telescope.
A stunning view of the starburst galaxy Messier 82, showing bright blue stars and glowing clouds of gas, captured by the Hubble Space Telescope.
A stunning view of the spiral galaxy NGC 4414, showcasing its starry core and dusty spiral arms as captured by the Hubble Space Telescope.
An old scientific drawing showing what our Milky Way Galaxy might look like, as imagined by astronomer William Herschel in 1785.
A beautiful view of the Andromeda galaxy, showing its glowing arms of new stars and the bright center filled with older stars.
A diagram showing different shapes of galaxies, helping us classify them in space.
A stunning view of the galaxy cluster Abell 1413, showing hundreds of galaxies and beautiful arcs created by gravitational lensing, captured by the Hubble Space Telescope.
A stunning view of the elliptical galaxy NGC 3923, located over 90 million light-years away, showcasing its unique layered star structure.
A stunning view of Hoag's Object, a rare ring galaxy, showing a bright ring of blue stars surrounding a yellow center, captured by NASA's Hubble Space Telescope.
A colorful view of the massive galaxy Hercules A, showing its glowing jets as seen by space and radio telescopes.
A colorful jet of energy streaming from the center of galaxy M87, captured by the Hubble Space Telescope.
The Seyfert's Sextet is a group of galaxies interacting in deep space, captured by the Hubble telescope.
A beautiful photograph of the Great Andromeda Nebula, a distant galaxy captured by astronomer Isaac Roberts in 1899.

This article is a child-friendly adaptation of the Wikipedia article on Galaxy, available under CC BY-SA 4.0.

Images from Wikimedia Commons. Tap any image to view credits and license.