If you have a genuine interest in the universe then I’m sure that you have this question in your mind “Why Planets are round and Galaxies are flat?”.
We know that in our universe planets and stars are round in shape whereas galaxies are flat.
There are two shapes seems to be in the universe round ( sphere) and flat (disc).
All of our planets and stars are of spherical shape and galaxies are of the disc-like shape, that is, flat. Today, Let’s talk about the reason.
It is due to some rules of physics. Let’s talk about the earth. We know that everything is bounded due to gravity.
In order to define gravity, we may say that it is the virtue of earth due to which it attracts everything.
The only reason that everything is held together is gravity.
Now, in order to discuss that the shape of the earth is round there comes out two main factors – Equilibrium and Symmetry.
Why Planets are round and Galaxies are flat?
First, Let’s talk about equilibrium.
For illustration let’s think that we have to build a bridge. The engineers know very well that to build a bridge every bolt, wires must be at the same positions. This is called the equilibrium position.
Obviously, the force must be in equilibrium.
So we have to make the pillars in a bridge in such a way that the pressure force and the gravitational force are in equilibrium.
On the other hand, let’s talk about the symmetry.
It also plays an important role. Symmetry means that if we roll the earth around any of the three axes, the shape will remain the same.
There will be no difference.
Thus, we have concluded that gravity plays an important role in the shape of any planet.
But not only gravity another thing which is also responsible for the round shapes of the planets is density.
As in the case of earth, we know that earth is almost a ball of iron which has almost billions trillions tons of weight, that is, the earth is really very massive.
Now we know very well that gravity is a weak force but when it works on such a massive ball, it becomes very strong and binds all the particles of the earth very strongly in a spherical shape.
But galaxies are less denser than planets and so the gravitational force which is a weak force is not able to bind up them into a ball.
Therefore galaxies are not spherical in shape.
Now, the reason behind the disc-like shapes of the galaxy is centrifugal force.
Centrifugal force is the force which acts on a body moving round away towards the centre of the body due to body’s inertia.
When a galaxy spins, its outer stars are pushed outwards while its outer stars remain closed under the gravitational pull.
This is the reason that galaxies are flat.
The process is similar to the solar system.
Hopefully, you understand Why Planets are round and Galaxies are flat.
Now, it’s your turn, Give your genuine review about this article “Why Planets are round and Galaxies are Flat” in the comment section.
Thanx for spending a really great good time with us if have a genuine interest in Astronauts & Space Science then you may like to read Why can’t we see Black Hole? & Elon Musk’s SpaceX Reveals the Incredible Sci-Fi Design for Starship articles.