Mick Hartley

Like many people, I suspect, I get my updates about physics from the odd article or review rather than ploughing through some book which I won’t understand anyway. If I’m going to read science, then I might as well read about stuff I’ve at least got some hope of making sense of, like genetics or neurobiology. With physics, you just have to take their word for it. String theory? Multiverses? Not a clue mate – you tell me.

I get the feeling that people who do buy physics books – apart of course from those few who genuinely understand what it’s all about – either like the look of them on their bookshelves, or get a perverse pleasure in being overawed by how clever these scientists are, or how weird the whole business of modern physics has become. Seven dimensions? Oscillating time? Fifty-seven varieties of quark, fourteen of them shaped like doughnuts? We’ll all be born again at the Omega Point? Blimey, would you believe it!

The point is, with physics it’s way past the stage where we, the non-specialists, can say, yes, that makes sense, or no, that’s pretty implausible. After quantum theory, it’s all implausible, and common sense doesn’t really come into it. All you can do is sit back and watch the physicists fight it out amongst themselves, and hope they wake us up when it’s all sorted out.

Anyway, here’s a nice example of the sort of article I’m thinking of:

In the 1990s…a new possibility arose, as scientists came to appreciate the role of “branes” in higher-dimensional physics. A brane, generalizing the concept of a membrane, is simply an extended object: A string is a one-dimensional brane, a membrane is a two-dimensional brane, and so on, up to however many dimensions may exist. A remarkable feature of such objects is that particles may be confined to them, unable to escape into the surrounding space. We can therefore imagine that our visible world is a three-dimensional brane, embedded in a larger universe into which we simply can’t reach.

Yes, I understand that! Perhaps I’m going to learn something here. But then…

Gravity, as the curvature of spacetime itself, is the one force that is hard to confine to a brane; the extra dimensions must therefore have some feature that prevents gravity from appearing higher-dimensional. (For example, in four spatial dimensions, the gravitational force would fall off as the distance cubed, rather than the distance squared.) One possibility, proposed by Nima Arkani-Hamed, Savas Dimopoulos and Georgi (“Gia”) Dvali, is that the extra dimensions curl up into a ball that is small without being too small—perhaps as large as a millimeter across in each direction.

The extra dimensions curl up into a ball a millimeter across? Why not spread out into a cube three miles across? Or spin around like a hula-hoop? Or mix with the crowds at Royal Ascot? There’s no way of evaluating any of this stuff unless you’re one of the few who can operate at that level. Like I said, you just have to take their word for it. It’s like reading about the origin myths of some newly discovered tribe from New Guinea: it may be interesting at some level to learn about these things, but really for us amateurs it’s just more weird stuff, which doesn’t connect to much else except insofar as it’s what some (admittedly very clever) people believe to be true.

(I could go off at this point about how this is the way some cultural theorists see all science, because, lacking any scientific understanding, they imagine it always has that arbitrary quality, which leads them down the dead-end of post-modernism where origin myths may be just as true as scientific theories – but I’ll refrain.)

Both books under review get a good write-up, but I doubt I’ll be reading them. I have this sneaking hope that some genius will come along at some point and tie it all together – quantum theory, relativity, the whole works – and it’ll turn out that it does make sense after all, and we can forget that bullshit about “Not only is the universe stranger than we imagine, it is stranger than we can imagine.” In the meantime why take up all that brain space, when in the end it’s “just somethin’ we’re gonna have to forget.”