Friday, August 28, 2015

Friday Science: Fabric of Cosmos 1

1. I had been reading a book called, Our Mathematical Universe. I got through the part of the book that is generally accepted by physicists of the universe. But I came to realize that most view the rest of the book not only speculative, but perhaps bordering on the irresponsibly speculative.

So I've switched to another book on the current state of physics: Brian Greene's The Fabric of the Cosmos. Now he is also speculative. He obviously likes string theory and the idea of multiple universes. I'm not real fond of either but at least these are well-trodden paths.

So I thought I'd dawdle through this book for a few Fridays. Chapter one is called "Roads to Reality: Space, Time, and Why Things Are as They Are."

2. The progression of the chapter is roughly:
  • Classical Reality
  • Relativistic Reality
  • Quantum Reality
  • Cosmological Reality
  • Past and Future Reality
The first half of this material will be familiar to the science enthusiast. He starts with Newton's sense that space and time are fixed entities in which we move. Einstein transformed our understanding here, for space and time become adjustable.

Entering the quantum reality apparently requires us to throw all our intuitions out the window. Here we encounter an idea I believe I first saw in Richard Feynman. Human intuitions were formed to help us survive and thrive in the macro-world. (I think you might say so whether you are speaking of how God made us or of how evolution developed us). The implication is that our "common sense" and our intuitions have no point of reference for the quantum world.

So the math seems to work, but no one really knows what it means. There are aspects of math itself that are are like this. Take Euler's famous equation from the 1700s: e - 1 = 0. What does it mean to raise something to the power of the square root of negative 1? I don't have a clue, but it works.

In the quantum world, at least so far, you cannot predict things. Rather, each event has a probability of happening. The universe is not determined. It is a game of chance.

3. When Greene gets to his section on cosmological reality, he covers some of the bases that I had been reading in Tegmark. One cosmological reality is the fact that the arrow of time only points in one direction. In theory, it would not have to be so. But the current sense of things is that something that happened very early in the history of the universe flipped the switch that makes time unidirectional.

Then he covers the big bang, the idea that the universe expanded rapidly into something like its current form from a much smaller version. He also mentions ideas new to me from Tegmark, which apparently have been around since the 70s and 80s--inflationary cosmology. This is a supposed period before the big bang when space itself expanded a million trillion trillion times in less than a millionth of a trillionth of a trillionth of a second.

4. What's missing is a grand unified theory that can reconcile both quantum mechanics and relativity. He seems to like Superstring theory and M theory. I sense increasing disgruntlement with these theories because there is no experimental data to suggest them whatsoever. They are completely hypothetical. Even Sheldon has given up on string theory. :-)

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