Galaxies- A Look Into the Stars

The science of astronomy has defined a galaxy as a system of stars, planets, dust, and other materials that revolve around a common center of mass. A galaxy can be very large and include billions of stars.

Photo Credit: Bryan Goff

Many galaxies have names. The names are often based on the constellation or the location of the star. Some galaxies have more interesting names than others. Most of these are named by astronomers who discovered them.

Spiral Galaxies

Spiral galaxies are the brightest galaxies that are far away. They are made up of stars and planets that are rotating in the opposite direction to shape the galaxy. There are lots of colors in the material in these galaxies. Another type of galaxy is an elliptical galaxy. These galaxies are shaped like grains of rice.

Galaxies are grouped together based on their gravitational attraction. Many galaxies are also grouped into clusters. One of these groups is the Local Group of 54 galaxies. This group includes our own Milky Way galaxy. It consists of hundreds of billions of stars.

spiral galaxy
Photo Credit: NASA

Types of Galaxies

Most modern catalogs of galaxies contain thousands of objects. The New General Catalog of Principal Galaxies, for example, has over 73,000 objects in it. When a new catalog is published, most of the objects have catalog designations. For instance, the Whirlpool Galaxy is a Messier object. Another example is the Pinwheel Galaxy, which is located in the Coma Benerices constellation.

Galaxies can be classified into three basic types. These are barred spiral, barred elliptical, and elliptical. While most are categorized by their size, some are still grouped by their shape. In general, a galaxy is a collection of planets and stars, but can also be a system of nebulae and dust.

The names of galaxies can vary, depending on how the catalog is compiled. Some galaxies are not included because they do not show up as separate objects in the sky. Others are only part of larger galaxy clusters. An example is the Sagittarius Dwarf Spheroidal Galaxy, which is not listed because it is not seen as a separate galaxy.

There are also a number of unusually shaped galaxies. These include galaxies in the process of colliding, and galaxies with active nuclei. These objects are thought to be in a transitory phase of galactic development.

Photo Credit: Greg Rakozy

Where Do Galaxies Get Their Names?

Several ancient cultures named ten thousand stars. However, there are only a few thousand that are bright enough for human observation with the naked eye. Using the names of stars and constellations is a great way to learn about outer space and the universe. You can also visit a planetarium to see displays of deep-space features.

Although it can be challenging to identify certain galaxies, the International Astronomical Union has produced several official catalogs. The New General Catalog of Nebulae and Star Clusters is the most widely used catalog. Other popular catalogs are the Atlas of Peculiar Galaxies, the Extragalactic Catalog, and the Markarian Catalog.