01-10-02, 02:17 AM
Could someone explain (briefly!) what M theory is, and voice their opinion on whether it sounds feasible? Is it a likely candidate for a Theory of Everything? From what I remember, string theory is a subset of M theory that arises naturally from M theory's precepts? Does M theory incorporate gravity? How many dimensions does it postulate?
I'm sure there are web sites (and books) out there but I'm a busy guy and I want the condensed form! And I want to hear some discussion from you guys!
P.S. I realize there is already a thread called "Superstring Theory.....How close?" but I want to inquire about M theory specifically.
01-10-02, 02:24 AM
Apart from the fact that instead of one there are five different, healthy theories of strings (three superstrings and two heterotic strings) there was another difficulty in studying these theories: we did not have tools to explore the theory over all possible values of the parameters in the theory. Each theory was like a large planet of which we only knew a small island somewhere on the planet. Techniques were developed to explore the theories more thoroughly, in other words, to travel around the seas in each of those planets and find new islands. And only then it was realized that those five string theories are actually islands on the same planet, not different ones! Thus there is an underlying theory of which all string theories are only different aspects. This was called M-theory. The M might stand for Mother of all theories or Mystery, because the planet we call M-theory is still largely unexplored.
There is still a third possibility for the M in M-theory. One of the islands that was found on the M-theory planet corresponds to a theory that lives not in 10 but in 11 dimensions. This seems to be telling us that M-theory should be viewed as an 11 dimensional theory that looks 10 dimensional at some points in its space of parameters. Such a theory could have as a fundamental object a Membrane, as opposed to a string. Like a drinking straw seen at a distance, the membranes would look like strings when we curl the 11th dimension into a small circle. ;)
nice one my /good man..........
that just removed the entire post that i intend to put up.
I suppose that all i can add is that Mtheory sprouts theories behind p-branes, membranes rather than 1d strings. I think.
merry belated xmas btw