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Chapter two

20:11 |

The Expanding Universe

 The second lecture in The Theory of Everything is regarding the expansion of the universe. This chapter begins by discussing our galaxy and some galaxies around us. Only in 1924 did American astronomer Edwin Hubble demonstrate that our universe was not the only galaxy. One of the first historic debates the chapter talks about is static vs expanding universe debates. The novel then continues on by discussing two main topics, beginning with the Friedmann Models. It states Friedmann's two assumptions: The universe looks identical in whichever direction we look, this also would be true if we were observing the universe from anywhere. This helped prove that our universe cannot be static. The chapter continues by talking about pieces of evidence which proved Hubble and Friedmann's beliefs and theories, such as Pennzias and Wilson along with Dicke and Peebles' discoveries. After this the book begins to discuss another very key topic, the Big Bang theory.  The book does not define nor explain what the Big Bang theory is, it simply tells us the beliefs before, during and after the implantation of the theory.







To rate the level of difficulty of this lecture, I would give it a 6/10. The vocabulary had been to my grade level, however the content was slightly more advanced than my capability of understanding. Initially the chapter starts by discussing the thoughts on the universe, and I came across some difficulty understanding the difference between static and non static- expanding universe. In order to figure out the differences between the two, I began by defining them. A static universe, also known as  " Einstein's universe"  it is an infinite and stationary universe. It is neither expanding nor contracting. To begin with, I did not understand the difference between an infinite and an expanding universe. In reality, I am still in darkness of what the differences are. Through a Youtube video (below), I began to understand a little. A static universe would mean that all galaxies are not moving, and all stars would be visible to us here on earth, however the galaxies are moving and the farther the galaxy, the faster it is moving.  What I need to yet research is from what central point are galaxies moving faster away from as you go further? Is there a center to the universe?




The Friedmann models did not create much confusion, what they did create were questions. His assumptions led to one major question. If the universe looks identical in whichever direction we look and that is true for everywhere else does that make our location in the universe special. I was unable to obtain a definite answer but from a certain article (attached below paragraph), I learned that our Earth is not in the center of the universe.  In Friedmann's models, all galaxies are moving directly away from each other. What the universe reminds me of is a inflating balloon which has spots on it (galaxies)- as the balloon expands, the distance between two spots increases. There is no spot that can be said to be the center of the expansion. What I found interesting were the 3 models of the universe which obey Friedmann's assumptions; 
  1.   The universe is expanding so slowly that the gravitational attraction between the different galaxies causes the expansion to slow down and eventually stop. 
    • The galaxies then would start to move towards eachother and the universe would contract 
    • The distance would begin at 0 reach maximum then go back to zero


     2.   The universe is expanding so rapidly that the gravitational attraction can never stop it, however with time it will slow down a little. 
    • The distance will begin at 0 then reach maximum, then go to a constant speed
     3.  The universe is expanding just fast enough to avoid recollapse
    • The disrance begins at  0 but will increase forever, the speed will get smaller and smaller but will never touch 0 again. 

http://www.spacedaily.com/reports/Theory_of_Earths_special_place_in_the_universe_proven_unfounded_999.html 

The Big Bang theory had to have been the greatest challenge yet. I did not know what the Big Bang had been, who created the theory nor any other information on it. After a lot of research I was able to discover what it was. I enjoyed my discovery so much that I created another page just for others to enjoy my learning in a grade level language! Other challenges I faced had been terminology. The book talk about the Doppler Effect, and I had to research that. Along with many other words. All I researched is on the next page (look at menu bar at top of page) (page labelled The Big Bang Theory of Dummies). 


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Posted by jagsosa