Why not start with a doozy?

"The Universe in a Nutshell"
By Stephen Hawking

I know it's not exactly easy Sunday reading, but I have been in quite a science kick lately. Last month, I was determined to read "A Brief History of Time" and I found it at Borders accompanied (within the same bindings) by one of Hawking's more recent publications, "The Universe in a Nutshell". Needless to say I reacted as if I had found a $100 bill in my pocket. I quickly got through "A Brief History" and decided to start blogging during "The Universe".

I found "A Brief History" to be very interesting and generally not impossible to follow. The version I have is illustrated, so the diagrams seem to help readers understand the concepts. However, in "The Universe", there are many more illustrations and they seem to take up at least 75% of the pages, with only about 25% of the pages containing ACTUAL TEXT. This is slightly disappointing and I have been pacing myself so this book will last me at least a week.

I am about halfway through "The Universe" and I think I am really starting to get a grasp on some of the theories and concepts in theoretical physics. Part of what possessed me to read both of these books was that I was fascinated by the idea that some people truly believe the earth is only 65,000 years old when it seems entirely logical that it is much, much older. I wanted to understand WHY we believe it is older and why we believe the universe is as old as it is.

One of the vignettes (page 78) describes the early universe moments after the big bang and paints sort of a timeline of events that took place in the billions of years following the big bang. I found this to be incredibly useful as it provides context for the creation of the universe. I know we cannot really comprehend what a billion years is, but if I can visualize a timeline of events in my head including the creation of the universe, the creation of the earth, the appearance of life on earth, and the appearance of HUMAN life on earth, I will feel somewhat satisfied with my own understanding of exactly where along the line the tiny blip we call human civilization falls (because it really is tiny). This vignette on page 78 describes the start of the universe as a singularity with an infinite temperature and infinite density and within one hundredth of a second the temperature would have been 100 billion degrees. At this point the universe would mostly have consisted of photons, electrons, and neutrinos (which are all light particles) and their antiparticles, together with some protons and neutrons. Next, for three minutes after the big bang the universe will have cooled to about one billion degrees (not too shabby, cooling 99 billion degrees in three minutes... I bet that even beats how quickly scrambled eggs cool) and protons and neutrons would have started to combine to form the nuclei of helium, hydrogen, and other light elements. Only hundreds of thousands of years later (!) will the temperature have dropped enough (to a few thousand degrees) to allow electrons to slow down to the point where they could begin to form atoms. The atoms that form at this point in time are not the kind of elements that make up life like carbon and oxygen. Those elements didn't come until much much later (billions of years later) from the burning of helium in the center of stars.

This insight into how scientists believe the early universe developed is very important as it describes why it is believed the universe is between 10 and 20 billion years old. I find breakdowns like these very helpful -- it is always good to take a step back and look at the big picture, for clarity sake.

Another good takeaway from the first half of this book was on page 34 -- The Rubber Sheet Analogy. I was having trouble understanding how large bodies (like stars) can warp spacetime and this analogy helped me to at least conceptualize it. If a large ball is placed on a rubber sheet it will cause the sheet to be curved near the ball so that if you try to roll another smaller ball across the sheet it will go around the larger ball.

That is all for now; I will savor the second half of this book and report back once finished.

=)