I’m reading cosmologist Max Tegmark’s Our Mathematical Universe: My Quest for the Ultimate Nature of Reality. I’m a sucker for popular science books on maths and physics, especially when they’re as well-written as this one. Max Tegmark argues that not only can our physical world be described by mathematics, but that it is a mathematical structure.
I don’t have the mathematical chops to refute that – although I’ve read in other books that a lot of maths is just about itself, and if we happen to come across another advanced civilization in our galaxy, their maths will look radically different from ours.
Be that as it may, this book is a gripping account of the writer’s exploration of the ultimate questions that have haunted hairless apes since they first climbed down from the trees: What is reality? Where did everything come from? How will it end?
I can’t condense 400 pages of insight into a mere blog post, but I will highlight some interesting points below:
1. Where does it all come from? About 14 billions years ago, a subatomic speck of non-diluting, inflating material repeatedly doubled itself until it was the size of an orange (but weighed about 1081 times more). This doubling (inflation) happened at the rate of every 10-38 seconds. 260 doublings were required to create the entire mass of our observable universe. The entire inflation process was, by our human standards, instantaneous – an exponential expansion in which something tiny grew explosively – the so-called “Big Bang”.
2. Why is there something rather than nothing? Everything that we see today – earth, sun, stars, galaxies – are the long-term result of quantum fluctuations in our initial inflating material. When inflation stretched a subatomic region into what is our observable universe, the density fluctuations got stretched as well, to the size of stars and galaxies.
3. Is space still expanding? Our universe is still expanding, albeit at a more relaxed pace – it doubles itself every 8 billion years. Every year, the outer limit of our observable universe increases as light from ever-more distant places reaches us. But as we look further into space, we look further back in time. We may reach the limit of what is observable, because that far back in time, galaxies had not yet had time to form.
4. How will it all end? Search me. Our universe is flat and will expand forever. Unbelievable as it seems, the theory of inflation explains this by saying that as long as inflation continues long enough to make the present, observable universe, it makes space flat enough to rule out any Big Chills or Big Crunches.
It gets a lot weirder than that. According to the theory of eternal inflation, our original inflating material cannot have stopped inflating. All it did was give rise to a non-inflating space – ours. It then continued inflating, giving rise to other spaces, other universes. It will do this forever. In other words, there are infinite parallel universes – we just can’t see them.
And just where did that original subatomic speck of non-diluting, inflating material come from?
No answers to that yet, and this is the point where I invoke the Goddess. 🙂