brane theory

Branes are really speculative at this point. They are an aspect of M theory, which currently doesn't even make any testible predictions. Interesting ideas, but nothing to put much value into.Ultimately, branes can be thought of as different ways of slicing a bulk 4D space. The same way a volume is a continuum of planes with boundary planes at each edge, a 4D bulk space would be bound by volumes, one of which is the universe we live in. The brane collision can be seen as the collapse of the extra large dimension in between boundary branes. It's kind of like squishing a volume into an area and then pulling it back.

With the existence of 7 extra dimensions (which no evidence supports even in the slightest) I don't think colliding branes is the simplest model at all. At least models like inflation work within the observable 4D universe we know of.

Actually, it merely states that the branes are embedded in a 5D bulk space. M theory while still requires the extra dimensions of string theory. Ockham's razor most certainly does not support the brane collision model, even if it was only a matter of adding one extra, unobservable dimension.[This message has been edited by Beercules, 03-22-2004]

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there is no theory that produces them, they are observations that do not fit the "standard model" so the model is "tweaked" to accomodate them

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That's exactly what M theory is - a model that is fine tuned to fit the current experimental evidence. In fact, all new scientific models are ad hoc in this way. In order for a hypothesis to be scientific, it must be consistent with the data. But science goes beyond that, requiring models to make testible predictions about the observable universe. Of course brane models attempt to do this as well, though technology does not allow for anything to be tested as of yet.On simplicity alone however, the brane model falls short because all it does is replace seemingly arbitrary fields with arbitrary dimensions, superstrings, branes and so on.[This message has been edited by Beercules, 03-22-2004]

And here I thought this board didn't support e-mail notification at all.

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I love reading what 'the man in the street' makes of these things...

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What does this mean? Surely you're not going to claim to be a physicist, right?

No, I will not be debating anything further with you.