If string theory is an extrapolation from the weak field limit of GR how will it ever make predictions?

Question

If string theory is an extrapolation from the weak field limit of GR how will it ever make predictions?

Answer 1

Your question doesn't make sense. The weak field limit of GR is Newtonian Gravity. String theory isn't an extrapolation of anything; it's an addition of one axiom to the existing axioms of Quantum Field Theory.

Answer 2

interpolation not extrapolation

Answer 3

For once I am answering this question without checking my facts. This is because as of yet very little of string theories' mathematics has filtered down to publications for the layman!



As far as I'm aware, string theory arose because of an approximation to the strong nuclear force. Somebody found that an equation made up of gamma functions (factorial n-1) could be plotted as a representation of the potential curve for the strong nuclear force. The strong nuclear force, allows freedom for partons when they are close but has infinite strength when the partons are separated by a significant (greater than the nuclear diameter) amount.



When this gamma function equation was subjected to one of Euler's non-linear differential equations, the product was a wave equation. This wave equation has solutions which propagate on very 'short-strings' or loops.



Thus, string theory has its origins in the approximation of the strong nuclear force and not electro-weak or other weak approximations. Hence, it has a strong theoretical footing but so far it has not described the world we see!