The history of mindset of our universe

The history of mindset of our universe

Today's blog is on the image of our universe. 

How the peoples thought about it and what they think at present?

Many theories given to explore this universe and many more. 

So, here we go👇👇👇👇

In earlier time, the people thought that the Earth is not sphere but it is flat plate.

And this flat plate is supported on the back of a giant tortoise. Once, the great scientist Bertrand Russell was giving the public lecture on astronomy. The lecture was going on in awesome way but at the end the old lady interrupted and said what the hell is this!

The whole world is the flat plate that is supported on the back of a giant tortoise. Well, for them the universe is infinite Tower of tortoise. And those all peoples were called as flat earthers . 

Flat earth supported by tortoise

Later, in 340 BC , Aristotle realised that the Earth is a sphere because when he observed the eclipse, the shadow of Earth on the Moon was in round shape. And that's enough for analysing the earth is sphere or flat plate.

If the earth is a flat plate then the eclipse should be in horizontal line but actually the eclipse is in the round shape only. Hence, Earth is sphere.

Shadow on moon if the earth is flat plate

The second argument by the Aristotle was that, the earth is stationary at its place and all the planets, moon, Sun and stars used to revolve around it. 

Ptolemy model of universe

In the year of 1514, the Nicolaus Copernicus given his idea that the sun is stationary and the earth and other planet use to revolve around it.

And at same time Johannes Kepler just modified the theory of capernicus that the planets don't move around the sun in circular orbits but basically it revolves in the elongated circular orbits or ellipse.

The time came to explain why these planets revolve around the sun. In 1687, there was the entry of great physicist Isaac Newton. Isaac Newton explained the motion of bodies in the space and time. Even, he had given many equations too.

He had given his universal law of gravitation that describes the one of the four fundamental forces of our universe. 

He stated, the gravitational force is attractive in nature that attract each and every body in the universe and this force is directly proportional to the product of their masses and inversely proportional to the square of the distance between their centres.

The following equation explains the force of gravitation that is given by Newton:- 

The equation of universal force of gravitation.

Later, the Newton realised that all the stars should be polite at some point due to the gravity. But it's not happening.

In 1691, Richard Bentley thought this will happen only if the finite number of stars spread in a finite region of space but it won't happen if there is infinite stars spread in the infinite region of space.

This is because in the infinite space there is not any centre where all they will collide. In infinite space any point can be taken as the centre.

At that time no one thought that the universe is expanding and contracting. They just thought the universe is static or unchanging. Even, they start making new concept of repulsive action of gravitational force. The new concept was that when the distance is larger enough then the gravitational force become repulsive in nature. But it was just pointless.

Now, in 1823 the scientist Heinrich Olbers raised the problem with infinite space. He said if the space is infinite then whether it is a day or night all the sight should be as brighter as star and if the star's light get interrupted by any object then also it start heating up itself and until it get as bright as star.

But to avoid this, it was amused that object is not heated up yet or the light might not yet have reached to us.

Now in 1915, Einstein had given his theory of general relativity in which he explained the gravity as the behaviour of space time curvature ( space time fabric is just a metaphor. It is just different thing. Space time is the fuse model of three dimension and the fourth dimension of time).
Even, the shifting of the orbit Mercury can be easily explained by his theory of general relativity. And it is most accurate theory till now.

In 1929, Edwin Hubble made Hubble telescope to observe the distant galaxies. He Observed the Galaxies are moving away from each other.
And by his observations, it is clear that the universe is expanding and there was the time when these all objects around us where closer to each other,even in a point.

And this time is called as the big bang, when the entire universe was Infinitely small and dense. This point is called as the singularity in which time doesn't exist nor the laws of Physics works.
I will discuss in my further blogs about big bang.

Well, today two theories can explain our entire universe, 1st theory of relativity and 2nd quantum mechanics. Theory of relativity can can explain our universe at very huge level like planets, stars ,black holes etc. Whereas quantum mechanics deals with the extremely small scale like atoms.

We are still searching the single theory that can explain our universe. Maybe it's string theory. But it isnt proved that.