And there are not just a few 'lost twins' of bits of early matter, but countlessly many: each of them zooming off, never to be seen by us, and also never to be seen by almost all other such bits of matter - or rather, by whatever observers those bits of matter might eventually aggregate into'. Well, the Big Bang is a tough topic to understand in detail! But a framework for understanding it, called inflationary cosmology, answers: Yes, it is so. The suggestion is this: at the Big Bang there could have been pieces of matter that went off in another direction than did all the matter that went on to form our galaxy - and moreover, in a different direction from all the matter that makes the Universe we can now observe - or even, will ever observe. Except that for Tegmark's level I, the birth in question is not yours, but the Universe's! Level I is rather like the idea that maybe, when you were born, you were one of two twins - but the other twin got separated from you at birth, to be brought up far away, so that you never had the chance to meet each other.

Thus the book begins with a nearly fatal bicycle accident which happened when he was a teenager (and the various quantum mechanical ways it might have been fatal!) and throughout the book, there are various anecdotes, for example about meeting the amazing Princeton physicist, John Wheeler. Besides, he combines all this science with personal anecdotes about his own life and times: from his growing up in Sweden, to his later career in the USA.

He writes clearly and wittily about all the mind-bending ideas which his book expounds: not just the established physics of relativity, cosmology and quantum physics, but also the controversial possibilities - those four main ways for the cosmos to be bigger and stranger than you would have thought - that he wants to convince you about. Then the second main way is the level II multiverse and so on till we get to the level IV multiverse.īut fear not: Max Tegmark is not only a gifted and distinguished cosmologist. So he calls the first main way it is bigger - the first main way he wants to surprise and unsettle you - the level I multiverse. Each represents such a vast extension of what we usually call the cosmos (or Universe) that he suggests we should use the word multiverse for these extensions. Tegmark argues that it is bigger and stranger in four main ways, each one building on the last. Indeed, it is bigger and stranger in ways you probably have not thought about - even though you are a reader of Plus, and so of course both very clever and very imaginative! The message of this book is that the cosmos is much bigger, and much stranger, than you might have thought. Our mathematical Universe: My quest for the ultimate nature of reality by Max Tegmark

Tegmark mathematical universe