Who named our galaxy the Milky Way? And why it is named so?

A galaxy is a large congregation of stars that are held together by a gravitational force at the center. These galaxies are often called island universes due to their sheer size. It is theorized that there are more than a trillion galaxies in the visible universe, which are the parts of the universe that our researchers and scientist have observed. Our home galaxy, the Milky Way, is one of 24 that belong to a collection of galaxies called the Local Group, and all of them travel in the same direction as to where the Milky Way is heading through space.

The Milky Way is a barred spiral galaxy. Its globular nucleus has a diameter of about 16,000 light-years. The galaxy has far-stretching spiral arms, and one of these arms is where our solar system is located. The Milky Way extends to up to 100,000 light-years in length and is approximated to consist of hundreds of billions of stars. Interestingly, the center of the galaxy is occupied by a massive black hole called the Sagittarius A* that could be controllingthe Milky Way’s gravitational force.

A distinct feature of the Milky Way is its bright band of light that runs across the center of its almost circular spiral shape. Upon closer inspection, the band is actually made up of millions of bright stars that are relatively close to one another, hence the reason why it looks like a band of light from afar. In 1610, astronomer Galileo Galilei was the first to discover using his telescope that the particular band of light in the night sky is formed by a multitude of stars. Many people believed that the galaxy got its name because of the milk-like color of its band at the center.

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Visual Galaxy: The Ultimate Guide to the Milky Way and Beyond
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The Realm of the Nebulae (The Silliman Memorial Lectures Series)

 

The Great Debate about the Milky Way

Before the 1920s, it is widely speculated that the Milky Way is comprised of all the stars in the universe. However, one astronomer named Heber Curtis wanted to prove that our concept of the universe is incorrect, as he believed that the Milky Way is just one out of billions or trillions of galaxies in the universe. In order for Curtis to properly present his evidence, a debate was held at the Smithsonian Museum of Natural History on the 26th of April in 1920. Curtis’ rival for the debate was Harlow Shapley, an astronomer who believed that the other discovered spiral nebulae, Andromeda, was a part of the bigger Milky Way Galaxy.

Curtis said that the Andromeda was a separate galaxy from the Milky Way due to the fact that the said galaxy has its own set of stars. If the Andromeda is indeed part of the Milky Way, Curtis asked why it has more stars in its location than any other sections of the Milky Way. He deemed this situation impossible and argued that the Andromeda is another galaxy because of its concentrated set of novae (a new star).

It was later revealed by Edwin Hubble, an astronomer based in the United States, that Curtis was right about the Milky Way being only one out of billions of galaxies in the known universe.

Milky Way’s Name

It is not actually clear as to who named our home galaxy the Milky Way, and the stories of its origins may have already been lost to history. However, there are various theories about how the Milky Way got its name. Long ago, the Roman Empire used to call the galaxy “Via Lactea,” a Latin phrase which means “road of milk” in English. But historians believed that the Romans got the name of the galaxy from the ancient Greeks, who named it “Galaxias Kyklos,” meaning “milky circle.” All these ancient words are owing to the appearance of the galaxy in the night sky, which looks like a long milky line.

On the other hand, there is a Greek myth about the formation of galaxies that may have influenced the creation of its name. According to the myth, the supreme leader of the Greek gods, Zeus, brought his son Heracles to Hera to be breastfed while she was sleeping. Zeus did this because he knew that Hera found out that Heracles was born from one of Zeus’ affairs and was a demi-god (half-mortal). When Hera woke up, Heracles was feeding, and she pushed the child away out of anger, causing a few drops of her milk to spill into the night sky. Hera’s milk drops then became the Milky Way.

Throughout history, other languages have developed different names for the Milky Way, though most of these names are believed to be variations of the Latin phrase. In Germany, the galaxy is called “Milchstrasse,” while in Norway, it is called “Melkeveien.” In almost all of the European languages, the word for the Milky Way is derived from the Latin name.

In China, the word for Milky Way means “silver river.” In Sanskrit, the galaxy’s name is “Mandakini,” meaning “calm.” The languages in South India refer to it as “Aakasha Ganga,” which means “Ganges of Space.” By looking at its different names, you will be able to deduce that the Milky Way’s appearance has contributed immensely to its nomenclature in various languages.