Expert: James Gort - 5/26/2007

Question
HELLO SIR,
I want to ask that according to string theory there was not any singularity at beginning of universe,the beginning was due to collision of two 3D membrane moving along a hidden dimension.but if it were to right there would be other universe in second membrane is that a acceptable idea?

also the membrane had 3(+1=4)dimension so how can they evolve 10D or 11D world that they themself predict?

Also they are highly speculative & have made no falsifiable prediction so why are we sticking to them for a consistent theory of quantum gravity?

Answer
Hi Mohit,

I'm not sure I can help much in this speculative area, but I'll try.

First, I hope you've had a chance to look at some of those books I recommended.  They can do much to help answer some of these questions.

To answer your first question, yes, I believe the theory you cite can allow for another universe (or even multiple universes).  One theory of the colliding branes allows for an infinite set of universes, many of which are "hidden" or degenerate until the collisions "opens them up" to 4 (or more) dimensions (our universe being one such case).

The 10D or 11D world is still theoretical.  One idea is that these dimensions always existed within the branes, but they were tightly "wrapped up" until an event (such as a collision) caused them to unwrap.

Some people are "sticking to them", but not everyone.  There are many roads to quantum gravity, and this is only one.  If you haven't yet read "Not Even Wrong", I urge you to do so.

The above may not have answered you questions entirely, because there are no good (or universally accepted) answers.  But keep thinking about the problem - and get those books if you can!

Prof. James Gort