Galaxy is a system bounded by a gravitational matter that contains millions of stars, star colonies, planets, suns etc. The word “Galaxy” came from the Greek word “Galaxias”. In an actual line, a group of millions of stars, dust and gases is called a Galaxy.
In the universe, there are millions and billions of galaxies. There is a far distance between these galaxies. A part of the galaxy is called “Milky Way”. These galaxies are much more significant than our thoughts. For example, the nearest galaxy contains 100 to 200 billion stars which radius are about 1,00,000 light-years and to make a circle around it, the sun, and it’s planets take time about 20,00,00,000 years. These galaxies contain star system, star clusters, solar system, planet etc. Besides that most galaxies got cosmic rays, black holes and interstellar medium of gas and dust.
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The starting of our universe was a massive blast. The history of these worlds started with a big explosion. The scientists gave name it as the “Big Bang”. From the theory of the creation of this universe, it is said that the Big Bang occurred about 13.82 billion years ago. The time before the Big bang there was nothing.
The whole universe was created from an atom. In a second there a big nuclear blast occurred and the fragment divided into much atomic energy and subatomic particles. Most of the gases were created like “Hydrogen”, “Helium”, “Lithium” as the form of giant clouds. When the time had been passed these energies and particles got closed and created the stars and suns. Like that millions of suns and stars got closed and formed the galaxies. The APM galaxy survey says that 15% of the sky contains about 3 million of galaxies.
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There are more like 170 billion galaxies in the universe that we can see and most of the galaxies intergalactic spaces are more like 1,000- 100,000 light-years. The galaxies are categorised by their shape or the visualisation we have. Most of the galaxies are “Elliptical Galaxy” with an ellipse shape.
There are also different shapes like disk shapes are called “Spiral Galaxy” and with no regular shape are called “Irregular shape”. These shapes are being created by their intergalactic attractions which cause extension of the galaxies. Sometimes it’s expanded so much that both galaxies turn into one “Starburst Galaxy” which is a form of the irregular galaxy. Some galaxies have been given the name by the scientists like “Andromeda Galaxy”, “Sombrero Galaxy”, “Whirlpool Galaxy” and many more. But of them are recognised by their codes from the astronomical catalogue like “NCG3992”, “CGCG269-023”, “PGC-37617” and many more.
We live in the galaxy named the “Milky Way”. It’s a massive disk-shaped spiral galaxy.
Different shapes of galaxies have the different type of speciality that holds them different from each other. There three shaped galaxies. They are- Ellipticals, Spirals and irregulars.Image Source
The elliptical galaxies get an ellipsoidal visualise. These galaxies have a low amount of clusters and have the decreasing rate of stars. For that reason, the stars don’t have the massive elements in them. They have smaller clusters. But most of the galaxies are big elliptical galaxies.
Sometimes the Starburst Galaxy turns into a giant Elliptical Galaxy for the sack of formation. The Spiral contains visible stars, materials like other galaxies, rotating star disks, interstellar medium with older stars. They have a fast rotation, and they are being visible because of their fairness and bulging. They have actual armed shape with logarithmic spirals. That’s why they are being called the spiral galaxy.
Our galaxy the Milky Way is the perfect example of the spiral galaxy. And the Irregular galaxies have the different type of random speciality that differs to others.
The galaxies are the most amazing thing out of the sky. It is a place of vast knowledge, and we have to explore it, discover it and know about it.