🌌 What is a galaxy?

A galaxy is a huge ocean of space consist of gas, dust, stars, planets, black hole, and many more that are held together with the force of gravity. We live on planet Earth which is a tiny part of the Milky Way galaxy.

Image Credit: NASA

Our planet Earth is part of the solar system which is also a small part of the Milky Way Galaxy. There are so many galaxies in our universe that we can’t even count but according to astronomers, there are about 125 billion galaxies in the observable universe.

Similar to other galaxies, our Milky Way galaxy is also composed of gas, dust, asteroids, planets, and billions of stars. You will be surprised to know that our Milky Way galaxy also has a massive black hole at its center.

Types of Galaxies

There are different types of galaxies in our universe that can be differ based on their color, shape, composition, and size that exist in our universe. Based on shape, galaxies can be categorized into mainly three types – spiral galaxy, elliptical galaxy, and irregular galaxy.

Spiral galaxies are flat and spiral-shaped galaxies that have massive old stars at the center and young stars arranged in spiral arms. Our Milky Way Galaxy is also a type of spiral galaxy.

Galaxies which have smooth and oval shape are elliptical galaxies. These are galaxies contain trillions of old and young stars that are held together by gravity.

Then there are some galaxies that are neither spiral nor elliptical in shape. They are known as irregular galaxies. As the name suggests, these galaxies don’t have any specific shape.

The above classification of galaxies is possible only due to the light coming from the stars present inside them. The shape of these galaxies can also be influenced by their neighboring galaxies.

Milky Way Galaxy

Our Milky Way galaxy contains our solar system and planet earth is a spiral galaxy. It is named as Milky Way due to its appearance as seen from the Earth. It is a milky band of light in the night sky formed due to the light coming from the stars present in it. It contains hundreds and thousands of stars, out of which Sun is the closest star to our planet Earth. 

Image Credit: NASA

Collisions between Galaxies

It is interesting to note that galaxies are not stationary in the universe. They continuously keep moving and sometimes two galaxies may even collide with each other. For example, the Andromeda galaxy is our nearest neighbor galaxy and it may collide with our Milky Way galaxy.

Professor Atom

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Professor Atom is a science enthusiast and alumni of IIT Bombay. According to him, every question can be solved with curiosity and mind mapping. ( Curiosity = Asking Questions = Learning )

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