Ideas About the Universe
The book The Illustrated Theory of Everything begins by explaining the different theories and ideas that physicists and philosophers have had in the past. The book initially explains the first published and popular theory by Aristotle in 340 B.C. Aristotle had been the first person to publish content on the fact that the earth is not flat, but rather a sphere. This chapter discusses many other discoveries, however the most significant one discussed had been Newtons in 1687. That year, Newton published the Principia Mathemalica Naturalis Causae. This document is believed to be the single most important documentation of all time. Not only did he put forward theories of how bodies moved in space and time, but also developed mathematics needed to analyze these motions. After discussing all of these theories before the 20th century, Stephen Hawking shifts his attention to post 20th century theories. In this section of the chapter, Hawking discusses how Newton's theory had been modified to state that large bodies repelled at large distances. But we learn that if stars came close, they would attract not repel, and that if stars began to move farther, the repulsive forces would dominate and stars would move farther. In this section we also learn that before the 20th century, they had believed that the universe had existed forever and was not expanding but stationary. However Edin Hubble tells us that the universe is always expanding, the stars are always moving away from us. I discovered in this section that 10-20 million years ago, all stars were together and this had been a result of the Big Bang. The Big Bang had been when the universe was "small" and indefinitely dense. The Big Bang had been the beginning of our time, anything before the Big Bang is not required to be known as it does not effect what has happened, what will happen or what is happening.
As I came from having absolute no background of physics or the universe, all this material had taken me quite a while to grasp. The initial reading had led no absolute no intake of any of the theories and information provided, however after the second and third read of this chapter I began to understand what Hawking was attempting to put forward. The fact that I borrowed the Illustrated version of Stephen Hawking's book greatly assisted me. The text of this novel is identical, however it is the footnotes, the images and the attractiveness of the book which assisted me in keeping my interest and helping a "rookie" physicist in learning about the origin and fate of the universe. In order to learn the information provided, I had to do a lot of outside of text research which included discussing my text with peers, using websites and youtube videos.
My adventure into learning about our universe all began by getting down the basics of what I would need to know. The first question that rose in my head had been "What is the universe?" , " what does it consist of" ? I goggled this question and found the famous Minute Physics. This video set a great foundation for me. I learned that the universe is everything. There are two definitions and types of the universe; Observable universe and the whole Universe. The observable universe is everything we know and can see. The whole universe is literally everything. It is the past, the present and the future. As far as we know, the universe is approximately 13.8 billion years old, and had a beginning. We do not know much on the universe, we know three things; space time, particles and how space time and particles interact to make everything. The next step for me had been to research some information on the Big Bang theory. After watching numerous videos, reading numerous webpages, I was able to learn some things however not much had been learned. The level of detail exceeds my understanding. I learned that it all began with electrons. Free electrons would cause photons light to scatter. Overtime, the electrons met a nuclei and created neutral atoms which after 380 000 years turned into light. One thing which blew my ming had been that the Big Bang theory was not an explosion but just an expansion.
This chapter has had to been one of my favourite chapters ever read. It is not often that a book is able to interest a teenager so much that instead of talking about his weekend he talks to his friends about what ideas were presented in his book. My favourite lines of this chapter had had to be; "... that brings us to the question of what could have caused the stars to have turned on in the first place". (8) After telling us that light from distant stars would be dimmed by absorption by intervening matter, and eventually the dimmed matter would begin to shine- which they do not. The only answer to this would be that the stars turned on at a finite point in time. What turned them on though? This thought has questioned me ever since I read it.
Secondary information found:
http://csep10.phys.utk.edu/astr161/lect/history/newtongrav.html
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