Note: This is something which I am doing for the first time. I am going to upload this blog in 2 parts because I feel like its too big and I don’t want to waste your time. Enjoy!
What are the biggest bodies in our universe? A star, a black hole or a neutron star, yes but all of them they don’t lie in empty space, right? They are inside galaxies. What is a galaxy? A galaxy is a system of stars, planets, huge clouds of gas and dust, probably black holes and a lot of other celestial objects. It may and mostly will contain star systems, will get to that later. It also contains planetary systems. The Galaxy which we live in is a neighbour of the Andromeda Galaxy and we believe that Our galaxy, The Milky Way is going to collide with the Andromeda in about 4.5 billion years. Mostly everything in this universe is inside galaxies, even galaxies are inside galaxies, the whole universe is made up of galaxies. So, let’s talk about galaxies.
Life Cycle of a Galaxy
Yes, there is something known as the life cycle of a galaxy, like a life cycle of a star. Galaxies contain billions to trillions of stars and celestial objects, they are huge. It would seem very imbecilic for an astrophysicist to think that galaxies are still being formed from scrap, as in meaning that they are not being formed like they were when the universe was just created. So, let’s talk about the birth of a galaxy.
Birth
When huge clouds of gas collided-because of fluctuations in the early density of the universe, they gave rise to dense regions of gas and dust which became the building blocks of galaxies.
Youth
During this stage, galaxies are shaped and many stars are formed, along with many star systems being rapidly formed at the same time. It really is a beautiful scene when all of these stars are being formed at the same time.
Maturity
In this phase, galaxies are set into a state of equilibrium where new stars are still being formed, star systems are settling in and new planetary systems are starting to form (FYI planetary system is a system like the solar system where there are planets, comets, moons, asteroids and 1 or 2 stars or black holes).
Decline
As galaxies age, new stars stop being formed, planetary systems settle in and galaxies are depleted of their interstellar gas reserves.
Death (or maybe not)
Most of the galaxies death comes when they merge with their neighbouring galaxies and form a bigger, a more spectacular galaxy, so basically they didn’t die at all. Although, some of them gradually stop forming stars, systems (both star and planetary) and get completely depleted of their gas reserves and after all of the stars and other celestial bodies in them die, they fade away into the darkness.
Did you know? There is a Supermassive Black Hole in the centre of our galaxy. Astronomers have come to the unanimous conclusion that mostly every big galaxy has a Supermassive Black Hole in its centre, but they are still not sure about it. There are types and shapes of galaxies. Let’s talk about the types of shape in galaxies first. It would have been better explanation with a picture but I can’t do that so I’ll just tell you the names of the shapes:-
1. Spiral Galaxies (They have spiral arms. Ex- The Milky Way, The Andromeda etc)
2. Elliptical Galaxies
3. Lenticular Galaxies
4. Irregular Galaxies
That was it for the first part, I will be back for the second part next week.
by,
Deeparsh Bhanot
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