There are many different kinds of galaxies. Our galaxy, the Milky Way, is a barred spiral galaxy. Some other types of galaxies include elliptical and irregular. The spiral galaxy is disk shaped with a ball in the center and arms that spiral outwards. Spiral galaxies have middle-aged stars and a good amount of gas while elliptical galaxies contain dust and small traces of gas. However, the typical irregular galaxy has an irregular or random shape with young stars and a vast amount of dust.
Early Galaxy Philosophies
In the past, many philosophers, scientists, and astronomers such as Democritus, Aristotle, and Olympiodorus the Younger have theorized what the Milky Way was. For example, Democritus, an early Greek philosopher, believed that the white streak in the night sky (now known as the Milky Way) consisted of different stars, while Olympiodorus the Younger believed that the Milky Way should have a parallax, or the difference in the apparent position of an object which is looked at from two very different lines of sight (like binoculars), which has been proven incorrect. The proof came later on by Galileo Galilei when he officially proved by using his telescope that the Milky Way was composed of a great number of faint stars. Later on around the 1920s Edwin Hubble began to observe our galaxy. He then came to the realization that we are just a needle in a haystack. Hubble showed that there are over 200 billion galaxies in the universe. The Milky Way contains roughly 200 to 400 billion stars and is 100,000 light-years in diameter. In fact, our galaxy is estimated to be 13.2 billion years old, which is nearly as old as the universe itself.
Telling the Age of the Milky Way
The individual stars in the Milky Way can also give us a reference to how old the Milky Way is. Scientists and astronomers can help detect the age of a star by measuring its radioactive elements. They then take the readings and compare them to the originals. When a white dwarf forms its surface temperature drops, which triggers radioactive cooling. When we measure this "cooling," we can compare them to their initial temperature and an estimate can then be made.
The Milky Way Is a Barred Spiral Galaxy
Moreover, our galaxy is not really just a spiral galaxy. It is correctly classified as a barred spiral galaxy. The barred spiral galaxy is a special kind of galaxy whose center simply has the appearance of a bar. But what exactly is this bar? The bar is simply a mechanism which channels gas. However, scientists have speculated that these bars aren't permanent. Eventually the bar will deteriorate, which will alter the galaxy into a regular spiral galaxy. The galactic center of our galaxy, believe it or not, currently harbors a supermassive black hole. Most galaxies are actually centered around a black hole. The black hole in the center of our galaxy is called Sagittarius A*.
The Milky Way is clustered nearby a set of local galaxies. One of these galaxies is the Andromeda Galaxy. This spiral galaxy is a whopping 2.5 million light-years away from Earth. It was recently found by astronomers in 2010 that the Andromeda Galaxy was formed by two galaxies that collapsed 9 billion years ago.
Gaining a better understanding of how the Milky Way came to be gives us a better understanding of how other galaxies can also harbor life. As we learn more about our own galaxy and further our understanding we can proceed to understand how other solar systems work in conjunction with ours.
Daniel Morales - Daniel Morales was involved with professional gamers, and semi-professional gamers during high school.
