The Different Types of Galaxies

The universe is filled with tons of galaxies. Each new galaxy that we discover reaffirms the literal truth that the universe is enormous. The definition of the word galaxy simple, all a galaxy is is a massive collection of stars, planets, dark matter, and globular clusters (groups of stars). There are also different types of galaxies, and this short article will go over the four types of galaxies as described by Edwin Hubble.

The first type of galaxy in Hubble’s classification (there are other, more complicated classifications) is the Spiral galaxy. Spiral galaxies are galaxies that have spiraled arms (which led to their name) and a bulge in the galactic center, the center of a galaxy which usually contains a supermassive black hole that keeps the stars orbiting and in balance. An example of a spiral galaxy would be the Andromeda galaxy, which is the largest galaxy in our local group.

The next type of galaxy is the Barred Spiral galaxy. The main difference between spiral and spiral barred galaxies is a bar in the center of a Barred Spiral galaxy, which is proposed to help nurture new stars. There are around twice as many Barred Spiral galaxies as there are Spiral galaxies. We live in a Barred Spiral galaxy, and that is the Milky Way.

A third type of galaxy is the elliptical galaxy. Unlike the previous two types of galaxies, elliptical galaxies do not have spiral arms but instead look like lenses. Elliptical galaxies are the extremes in terms of size, they are both the largest and smallest galaxies in our universe. When magnified, elliptical galaxies look like a whole bunch of dots. An example of an elliptical galaxy is the Sagittarius Dwarf Spherical Galaxy.

The fourth and last type of galaxy is the irregular galaxy.  Irregular galaxies are like oddball galaxies, each one looking completely different. Some may have a little bit of structure, but not enough to group it as one of the previous three types. Others have absolutely no structure at all and are almost like lumpy masses of stars. The Magellanic Clouds are irregular galaxies.

This is the easiest and simplest system of galaxy classification, and is an easy way to identify galaxies for any purpose. Perhaps this system is complete and there aren’t any other types of galaxies out there, but maybe it isn’t complete, since there are billions of galaxies that we can’t observe, and a new type is awaiting our discovery. We may never know the answer in our lifetimes, but as we explore the universe, we explore what God had created.

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