“Cosmology: A Very Short Introduction” by Peter Coles

Cosmology by Peter ColesCosmology: A Very Short IntroductionPeter Coles
Oxford University Press

This was the third and best of the astronomy-related Very Short Introductions I have read for my International Year of Astronomy Reading Challenge. Cosmology: A Very Short Introduction is well written and organized, and treats extremely difficult subjects in a very down to earth and sometimes humorous way. Relativity, particle physics, quantum mechanics, and the Big Bang are all presented in a way anyone can understand and see how they relate to cosmology, without getting into all the nasty mathematics.  But Peter Coles does more than explain the science of cosmology—the search to understand the nature, origins, and fate of the universe—he also shares some of the journeys science has taken towards understanding the universe. He shows how discoveries are built, one upon the other, how work in disparate fields can be brought together to find answers, and how the work of some scientists can be lost and forgotten, or recovered and brought forward. When he reaches the limits of knowledge, he doesn’t stop but describes some of the theories competing to make the next step forward.  That makes this an excellent book not just for teaching some basics of cosmology, but also teaching how science works.

There is just one little problem with this otherwise excellent book: it is out of date. In the mere 8 years since it was published, cosmologists have made phenomenal progress in substantiating some of the theories that Coles presents as mere possible alternatives. For instance we now know what the Universe is made of: 4% “baryonic” matter, of which we are made; 23% cold dark matter, which doesn’t do much other than gravitate; and 73% dark energy, which seems to gravitate in reverse. This adds up to a Universe that is geometrically “flat,” a concept that is difficult to explain but absolutely fundamental to cosmology. Most people have also heard by now that the Universe is expanding, and at an ever-increasing rate—thanks to dark energy. That answers another major question in cosmology, and has reduced the age of the Universe from an estimate of 15 billion years when this book was written to about 13.7 billion years.

The reason I know all this is because I had already read Galaxies: A Very Short Introduction, which describes these great discoveries at some length. At the time I criticized the book for straying off topic, but now I am glad of it because I might not have known about them otherwise. I don’t think I can overstate the importance of these discoveries—it is a privilege to be alive at a time when a picture of the whole universe, from beginning to end, is starting to come together. There is still the problem of the initial state of the Big Bang—as far as our theories can tell, it was a time (if time even existed then) of infinite density and infinite temperature, which is impossible—not to mention trying to figure out what the heck cold dark matter and dark energy are. But knowing the fundamental properties of the Universe—the “ΛCDM” or “standard” model—is, as the author of Galaxies puts it, “one of the great triumphs of science.” Hurrah for humans!

I would still recommend reading this book, but I would read it with, and before, Galaxies. The two books complement each other well, and by reading Cosmology first you set up a delicious mystery that gets solved, at least partially, in Galaxies. The two books together are a wild ride through all that is. I can only hope that both of them will soon be obsolete as we discover more about this amazing Universe of ours.

Galaxy M101 from the Hubble Space Telescope

The “Pinwheel Galaxy” (M101/NGC 5457) as seen by the Hubble Space Telescope.


4 comments on ““Cosmology: A Very Short Introduction” by Peter Coles

  1. somanybooks says:

    That is sometimes the problem with science books, yes? Even though they are recent new discoveries are made so often that the books are out of date before you know it.

  2. Sylvia says:

    Yes. I sometimes gripe about how college textbooks are now paperbacks, but maybe there is some wisdom in that. If only they weren't so outrageously overpriced that you can never replace them! I still rely on my old hardcover textbooks, but I wonder what I'm missing.

    My dad tried to give me his little old astronomy textbook from the 60s. He thinks it's still perfectly good and that they haven't discovered anything significant since then. Nothing I say can convince him otherwise. I hope I never end up like that. I want to always be ready to give up what I think I know.

  3. Michele Hush says:

    It is far from classical, but I found Philip Plait's “Death from the Skies — the Science Behind the End of the World” as informative as it is hilarious. In the course of explaining (and detailing the odds of) various scenarios for the destruction of our planet and universe, he imparts a good bit of astrophysics.

  4. Sylvia says:

    Hi Michele! That sounds like an entertaining book. I've heard some of those theories, and it's certainly a fun way to teach some astrophysics. Here's hoping we develop the technology so we can move to Europa in time to avoid getting barbecued by the Sun's red giant phase… 😉

Comments are closed.