Yesterday I was talking about the hypersphere as one of the proposed shapes for the universe, but I ran out of space (trying to keep things snappy) before I got to the more interesting idea. Some theories peg the universe as having no shape at all… it just goes on forever.
Have you ever heard the expression that an infinite number of monkeys banging away on an infinite number of typewriters will eventually produce the complete works of William Shakespeare? Statistically, that is a guaranteed fact. Given enough time, the “random sequence” of letters that correspond with Hamlet will eventually turn up. That’s the curious thing about infinity.
If the universe is truly infinite, that means Shakespeare was not the only Shakespeare. If you traveled far enough you would come across another galaxy, with another solar system, and another planet very much like earth. (having been formed with the same random sequence of evolutions) Walking this planet would be people very much like you and I. It may be off by a bit… Mary would actually be Sara, and with red hair rather than brown. Their pet dogs would have six legs.
Given enough distance covered in the infinite sequence, you will eventually stumble upon a place which is identical in every way to Earth, with identical people hanging around. Actually, the physicist Max Tegmark once calculated (for fun) how far away this mirror world would likely be according to the mathematics of probability:
A mere 10 to the power of 1029 meters. That’s a 1 with 100 000 000 000 000 000 000 000 000 000 zeros behind it.
In fact, if the universe goes on forever then anything that you can imagine… exists. It sounds crazy, but that is actually the simplest answer regarding the universe. It’s easy to explain how everything exists. However, it’s very difficult to explain why some things would exists while others would not. The question becomes the dividing line between can exist and can’t exist. How would such a rule come about? Does that mean our “laws of nature” are not universal?
Finally we come to the theory that the universe may not be the universe, but rather one little puddle of space in the infinite multiverse. As such, each pocket universe can be distinct unto itself, mind-numbingly large, but not infinite. More interestingly, each universe can then have it’s own unique set of natural laws forged as the universe was born.
As I said in Part 1, all this is theory. There is no way for us to know things on this scale, as we cannot see that far. The speed of light and the “cosmic horizon” means we can only observe a (relatively) very small portion of space around us. But as Richard Feynman said… “It’s fun to imagine!”