How Astronomical Research Starts.
Hey, Friends how are you, today we are discussion about the concepts of a great book written by Sir Stephen W Hawking "The Theory of Every Thing".
In this series I am going to give a brief outline of the history of Universe from Big Bang to Black Holes.
Ideas about the universe:
In the first segment of this book Sir Stephen Hawking tell about the book "On the Heavens" written by Aristotle. This book was able to put forward two good arguments which proves that Earth was a round ball rather than a flat plate.
Aristotle realized that eclipses of the moon were caused due to the Earth because it comes between the sun and the moon. In this segment he also proved that Earth was spherical and sun is the center of our Solar system.
Due to the travelling experience of the Greeks we are able to say that the Pole star appeared lower in the sky when viewed in the south than it did in more northerly regions.
Aristotle even assumed the distance around the sun was four hundred thousand stadia. We don't know exactly what length a stadium was, but it may have been about two hundred yards. Due to this explanation Aristotle's estimate about twice the currently accepted figure.
It seemed to Aristotle that the Earth is still there and that the sun, the moon, the planets, and the stars revolves around Earth. He believed this due to some special reasons that the Earth was the center of the universe.
This idea was elaborated by Ptolemy by the help of complete cosmological model. He explained that the Earth is in the middle and eight balls revolves around it, which includes the moon, the sun, the stars and the five planets known at that time: Mercury, Venus, Mars, Jupiter and Saturn.
Ptolemy's model provided a reasonably accurate system for predicting the positions of heavenly bodies in the sky.
A simpler model, was proposed in 1514 by a Polish priest, Nicholas Copernicus. His idea is that the sun was stationary at the center and that the Earth and the planets moved in circular orbits around the sun.
But this idea was not be taken seriously for nearly a century.
But, after a century two astronomers Johannes Kepler and Galileo Galilei started to support the Copernican theory. The death of the Aristotelian theory came in 1609.
For many years Galileo observing the night sky with the help of a telescope which is just invented.
When Galileo looked at the planet Jupiter, he see that the Jupiter is surrounded by many small satellites, and moons, which is orbited around it. At the same time, Kepler had modified Copernicus's theory, suggesting that the planets moved not in circles, but in ellipses. By this time the subject had become a topic of very important discussion. Everyone had their own conspiracy theory, and who was right and who was wrong, nobody knows anything. Just people were doing research and the result of this was that we came to know about the Reality of Universe.
Today we know Various things about the planets, stars, solar system, Black holes and universe. If this researches were not done then I think today we don't know much about the universe.
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