Thursday, 28 July 2016

Review: A Brief History of Time

Hi all! I’ve just finished A Brief History of Time by Stephen Hawking, which I started back in April or May but put down by about page 20 because I just couldn’t get through it at the time. But I started reading it again a few days ago and have at last managed to finish it.

In short, it covers an enormous range of important topics in cosmology and quantum physics in only two hundred pages, and thus it is not by any means an easy read. Some topics it covers include redshift, the cosmic microwave background, Friedmann models of the universe, Penrose & Hawking Big Bang proof, the Heisenberg uncertainty principle, Pauli’s exclusion principle, the six flavours and three colours of quarks, the concept of spin, antiparticles, photons and other virtual particles, Z and W bosons, The Higgs particle, the relationship between mass of a particle and range of a force, quark confinement, the effect of high energies on the strong, weak and electromagnetic forces, grand unification energy, CPT symmetry, light cones, and, surprisingly, the Catholic church and its follies in physics.

So … a lot, basically.

The book has some major cons: being a very heavy read, being out of date (published in 1988 originally), and being incredibly bloody frustrating. Now, the frustration comes not from any flaw in the writing, but in Hawking’s information on the latest theories in physics (well, in 1988) which unfortunately were not at all to my taste. Heisenberg uncertainty and the finite speed of light and wave-particle duality and the idea of force-carrying particles all deeply annoy me, even though they’re well-established. I miss the times when physics wasn’t completely counter-intuitive.

Presumably I’ll get more used to these ideas once I’m studying Physics in college this September, but in a way I suppose my scepticism is good, because it lets me look at the evidence from scratch(ish) and come to conclusions rather than just being brought up with the idea of string theory etc. It means I’m more likely to have fresh perspectives on it (and also more likely to find out that, oops, someone already thought of that thirty years ago).

Hawking was quite witty throughout the book, and I especially liked his account of a conference held in the Vatican for the world’s leading cosmologists, in which the Pope told the cosmologists that it was alright to study what happened after the Big Bang, but that they shouldn’t meddle in understanding the Big Bang itself because that was God’s work. You’d think the Catholic Church would have learned with Galileo not to mess with physics, but clearly not.

I also enjoyed the deeper level of understanding the book gave me of a ton of concepts mentioned briefly in Leaving Cert Chemistry – an explanation of the Heisenberg Uncertainty Principle, for example. In LC Chem, we learned “The Heisenberg uncertainty principle states that it is impossible to determine at the same time the exact position and velocity of an electron”, but in A Brief History of Time Hawking explains that the more precisely you know the position, the less precisely you know the velocity, because you have to use a quantum of light to “see” the position and that disturbs the electron, changing its velocity.

The death of scientific determinism saddens me, even though it happened a hundred years ago. Einstein clearly felt similarly, with “God does not play dice” – it’s so disappointing to spend thousands of years slowly understanding the world and then hit up against this insurmountable physical barrier, that doesn’t care how smart you are or how good your instrument is. I’m very frustrated by the idea that there are some things you just can’t know, and honestly I haven’t yet accepted it (or particle-wave duality).

Another thing that frustrates me is how Physics in some ways seems to be doing the annoying that biology does, which is just classifying things. Dear Physics: please keep answering the ‘why’s. I didn’t know I’d grow up and want to be a physicist, but I did know I spent most of my waking hours playing the why game, and I don’t want that to stop.

Also: UNIFYING FORCES. I enjoyed reading about the grand unification energy, which would be a high energy at which the strength of the strong nuclear, weak nuclear and electromagnetic forces is the same, because the strong force is weaker at high energies while the weak and electromagnetic forces are stronger. But yes, hopefully gravity can get in on the game.

I’m still waiting for the theory of everything, and by waiting I mean starting out on my journey of learning physics properly so I can contribute and understand the universe. I hope this grand theory is discovered in my lifetime, and that I can have a part in it.

Final thoughts: space. It’s cool.

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