He does a pretty good job of explaining things and keeping it simple. Some parts were very interesting. Other parts went right over my head ( )

An excellent Popular Science trip through the bits that just seem weird with one of the world's great cosmologists. Sir Martin manages to keep things just about understandable for someone who needs to remind himself which one lambda is, but thinks it's Einstein's one.

It's 20 years since this was published and that means I'm off to figure out what's moved on as I certainly know parts have, but I'll feel more comfortable so doing having read this book. ( )

(original review, 2000)

If there was an infinite number of universes wouldn't there be a universe in which a mad scientist had discovered how to destroy all the universes and pressed the button, so there would be nothing at all? But then there would also be a good scientist who devised a plan to stop the mad scientist from pressing the button in the first place! What if they are one & the same, who wins? But as with Madeira Island's Nationalism, the bad scientist would only have to succeed once.

Fine tuning suggests that the Universe is at it is because in effect that's how it has to be therefore the creator is not malevolent. Believers would believe that the Universe is fine tuned whilst atheists would not. Therefore Devil's Advocate likes attributing believers with atheist views to lay a charge of brutality malevolent when in actual fact the malevolent theory is their own. Devil's Advocate has missed the fact that if you don't believe in fine tuning and you don't believe in God then you are laying the blame for random cruelty on evolution. The reverse is not true because believers accept fine tuning:
God + Belief + Fine tuning = No Malevolence (according to Dawkin’s argument);
Atheism + randomness + evolution = Biology professor criticising the welfare state for allowing thick yobs too have too many kids.

So, is there a universe somewhere in which every Tom, Dick and Harry et al are decent talented principled intelligent informed people with nothing but social & environmental good at heart & in action? Ah, well, clearly the multiverse hypothesis has just been irrevocably debunked. Pity. Nah. Nor really. There are definitely multiverses. They exist on the far side of infinity. More importantly, did my cat Ilsa go to heaven? I'm not sure. Maybe she's God in a reverse multiverse. And perhaps (nay, certainly) also a universe in which the multiverse theory does not apply. (*head explodes*) But what do I know. I'm too thick to understand any of this. More importantly: Can Benfica win the Portuguese League this year, that's what I want to know. Sure can. In the universe 3 universes over, they win it with a team made up entirely of dachshunds!

Seriously, the many-worlds interpretation isn't really about the universe splitting per se, the goal is to avoid the problem of wavefunction collapse that is invoked in measurement. The principle of superposition means that we can create states that are, for example, half spin up and half spin down. When we make a measurement of the spin, the wavefunction collapses into only one of these states. However, these measurement processes are qualitatively different from unobserved processes, which allow the wavefunction to evolve smoothly with time. This has led to a lot of discussions about the role of observers in quantum mechanics (Schrödinger's cat, etc.). The basic idea of many worlds is that there is nothing special about measurement. The wavefunction only appears to collapse to the (necessarily quantum) observer, but all possible universes coexist in the same way that the states spin up and down can coexist for the electron. ( )

I happened across this book when putting away something else. I decided to read it - it's small, and should go quickly. Which it did.
I say 3 and a half stars.
It was an enjoyable read, even if a lot of supporting detail for the numbers and conclusions had to be omitted. I think the book was aimed at people who know less physics than I do. I'm sure it was aimed at people who know less math than I do. I did REALLY like some of the quotes for the chapter headings.
The book was written late in the 20th century, and the author speculated that a lot of open questions in cosmology would be answered within 5 years. It's been 3 times that long, and as far as I can tell, the cosmologists are still debating the answers.
A lot of popular science writers have jumped on the multiverse bandwagon, and I appreciate that this guy makes it clear that the multiverse is one possible explanation, but that other ideas may emerge.
( )

You may be familiar with a so called “proof” for the existence of a creator [or do I mean “Creator” (?)] from the apparent design of [his or her] creatures. This argument has been pretty much debunked as it applies to living animals by (1) the theory of evolution and (2) a deep understanding how the phenomenon of emergence can result in complex order arising from randomness despite the second law of thermodynamics. Nonetheless, it does seem as if the earth is very well suited for human life and probably will continue to be so unless climate change deniers prevent sensible people from taking steps necessary to protect our environment.

Indeed, the fact that human life evolved as it did seems to be dependent on the fact that a number of ratios of physical phenomena fall within some very sensitive parameters. Martin Rees, a Royal Society Research Professor at Cambridge University, who was also the official Astronomer Royal of Great Britain, wrote a very interesting book in 1999 that explored the sensitivity of six of those parameters, which he argues are fundamental to modern physics and the known structure of the universe.

Rees observes that each of these ratios has to fall within a very narrow range or, for example (in no particular order): (1) atoms could not have formed after the Big Bang, (2) galaxies could not have formed, (3) the universe would have already collapsed upon itself, (4) the nuclear power generated at the core of the sun would not diffuse outward at just the right rate to balance the heat lost at the surface, and (5) there could be no complex chemistry, atoms larger than helium being unstable.

Although arguing that the universe is spookily “fine tuned,” Rees draws no conclusions as to whether a benign Creator made it so. Other sources like YouTube indicate that he is an atheist. Instead of God, he discusses the cosmological theory of the “multiverse,” the possibility that there are many, if not an infinite number of, other universes that are not as finely tuned as our own. In such a case, the anthropic principal dictates that our universe is finely tuned for human benefit because if it were not, we would not be here!

Evaluation: This book is well worth reading for a lot of reasons. It gives a lucid explication of many physics principles and serves as an excellent introduction to advances in cosmology. I would quibble with the premise that all the constants are “fine tuned,” but his argument that human life depends on several of them falling within narrow limits appears irrefutable.

(JAB) ( )