Galaxies: Islands in the Vast Ocean of Space

Many people know what galaxies are, however, many do not know what makes up a galaxy or what they contain. The galaxy is made up of three main things. Let's begin with stars and gas. Our galaxy has arms made of bright stars and glowing clouds of gas that curl into a spiral shape. Galaxies contain billions of stars, more than we could ever count and between all the stars there is empty space.

Everything within a galaxy creates one of three unique galaxy shapes: spiral, elliptical and irregular. Spiral galaxies look like pinwheels, such as the Milky Way. The middle looks like a disk and the older stars are in the center. The youngest stars are in the arms outside since that’s where gas and dust meet to create new stars.

Elliptical galaxies are shaped like a loaf of bread or football. Did you know that most of the stars are in the middle? There are more elliptical galaxies than the other types of galaxies. Unlike spiral and elliptical galaxies, irregular galaxies aren’t formed in any distintable shape. These galaxies seem chaotic in shape since they are created when various galaxies collide with another. Although this sounds scary, it is not a big deal since it is mainly empty space between the stars and planets. Interestingly, our Milky Way galaxy will collide with the Andromeda galaxy, the Milky Way’s nearest galactic neighbor, in about five billion years.

Originally, scientists believed that all of the stars and planets in the cosmos were part of a single massive cluster. However in 1917, Thomas Wright proposed that there could be numerous clusters of stars and planets. It wasn't too long after that astronomers had confirmed this idea. Now, systems of stars, planets, dust, gas and dark matter are known as galaxies.

[Sources: 100 Things To Know About Space; Britannica Kids]

Great article, with good information and facts. Nice including dates. – Aviana houseCardinal heights upper middle school (2022-01-09 15:32)