h2g2 The Hitchhiker's Guide to the Galaxy: Earth Edition

when the f**k are you on about?
I make a habit of disregarding anything written by someone who thinks that they are made of supernoodles.

Well, you're going to have to make a habit then of disregarding anything said by lots of phycisists, because lots of them believe we may very well be made of supernoodles.

Hmmmm,.. noodles

It's true, pick up the book "The Elegant Universe" by Brian Greene, it's written in a way that it explains everything in such a way you don't need a degree in physics to understand it. A definite recommended read.

Okay, so the supernoodles are worrying (and indeed, the strings that are 10 to the minus 33 cms may taste better) but who is to say that there aren't other dimensions, and until someone finds definate proof that there are only four dimensions (line, area, volume and time) it is a little unfair to just disregard this theory. The question that springs to my mind is how on earth did they ever start thinking of this string or membrane theory...it must have been a very stange path of thought that came up with this conclusion. Another question that has been bothering me for some time is, if there are eleven or ten, or twenty-six, or twelve, maybe even forty-two (which would explain alot of things) dimensions, then what do the ones that aren't line, area, volume, time and the one where the membranes exist contain? I can understand how they might be curled up in a little ball hiding somewhere, but what do they consist of?

I have read a book about this theory, but could not understand it very well. But the question I think of when faced with extra dimensions is this:
Space and Time are dimensions that act in very different ways. So why should these hypothetical dimensions not have been noticed? Perhaps it is just that due to them acting in different ways, we do not usually consider them to be dimensions.
Take mass. Perhaps it has a dimension, and an objects having mass transports it a distance along this dimension.
The general theory of relativity said that space-time was bent by mass, giving rise to gravity. Perhaps a similar effect occuring through some other dimensions may be responsible for other forces. Perhaps a charged particle exists because it has moved along the charge dimension, and the presence of an electrical charge would bend space along this dimension.

Do any more scientifically knowledgeable people wish to comment on the feasibility of this theory?

The reason for the extra dimensions is that basically there was electromagnetism, then relativity turned up and said that electromegnetism meant we were wrong about gravity, speed, measurement and ... well, more or less everything except electromegnetism, and then quantum mechanics turned up and pointed out we were wrong about that, too.

Dirac came up with a bright theory called QED to try and help out, but then the only way to try and calculate certain things was to "renormalize" them -- the maths said that certain things were infinite in value in certain places and they therefore had to be divided by infinite quantities so we could measure them.

This is, of course, impossible.

A number of other physicists used symmetry groups and the Quark theory to try and help out but many of the problems of renormalization remained.

String theory provided a get-out.

The reason string theory is held to be so plausible is that if you suddenly don't have to divide things by infinite quantities any more, a few spare dimensions aren't going to make you quibble. There is, presently, not one shred of experimental evidence for it (as opposed to any other quantum field theories), but it's the best we've got mathematically. And since all we're doing is modelling the thing anyway, who cares?

(Interesting point. The Schordinger Equation describes a "wavefunction", which is what it sounds like -- a function describing a little ripply thing of a certain, known, size. A wavefunction cannot be directly measured, yet it is the only way of accounting for certain tiny physical effects in quantum mechanics. Therefore many people believe that it (or something embodying it) is "real", since its effects are visible even if it is not. Quarks are believed to be real in the same way (Quarks cannot exist in isolation, but only in combination with at least one other antiquark or two other quarks), and strings may turn out to be much the same.)

Hey ZikesMan,

Isn't technology wonderful . Reading these postings, I came across your book recommendation. I quickly popped across to my local library's site, did a search for the book (didn't even have to type anything, just copied & pasted), placed it on hold, then popped back to read the rest of the postings .

Thanks for the recommendation, by the way.
I'm currently reading "How the universe got it's spots" by Janna Levin. It's written in a diary format, in colloquial style. Very easy to read. I haven't gotten to the bit about string theory yet, but it will be interesting to see what she says.