# Quantum Gravity "Strings" Theory Origin

I was reading some introductory stuff on various websites about the string theory of quantum gravity which postulates that among other things-

http://www.strings.ph.qmw.ac.uk/WhatIs/what.html

“What string theory does is to replace the point particles of QFTs with extended 1-dimensional objects, strings, with length of the order of 10^-33mm, termed the ‘Planck length’. What one is then dealing with is a QFT on the 2-dimensional ‘world-surface’ of the string as it moves through time, embedded within spacetime itself. The first effect of this is to ‘smooth out’ interactions in such a way that UV behaviour remains finite. Also, one finds that such a theory can be used to describe gravitational interactions in an entirely natural way.”

I have not found anything on these sites as to why a “Planck Limit” object makes intuitive or empirical sense as the mediating, 10 dimensional sub-quantum ether through and by which electromagnetic, weak and strong nuclear force and gravitational interactions take place. It’s almost as if they are saying “Well the math works pretty well with strings so were going to pretend it’s true for now.”

Obviously this take on the subject is wrong headed or so many math and science geniuses wouldn’t be tackling the work involved in parsing out a deci-dimensional “theory of everything”. Barbie was right - this math is hard.

So why little Planck length strings? Why must or should these exist other than enabling equations to close properly?

Since nobody else has answered yet, I’ll give you my meager understanding.

Someone (don’t know who) was looking for equations to describe poperties of elementary particles. He found equations which fit in many ways, although they had an annoying lowest energy state which didn’t seem to exist in nature. After some time, someone realized the equations described oscillations of classical stings. At some (I’m pretty sure later) time, someone else realized that if you kicked up the tension really really high, the lowest energy particles seemd to fit with the expected properties of gravitons.

So the equations existed before they were linked with strings.

This memory was probably brought to you by Brian Greene’s The Elegant Universe, which I recommend.

Hope this helps.

String theory originally only worked to describe bosons. For instance quarks inside hadrons are held together by the exchange of gluons and the effect is (very loosely) as if the quarks are held together by elastic strings thus the math was called string theory.

And this memory was probably, also, brought to you by Brian Greene’s The Elegant Universe.

IMHO when all is said and done we’ll find that we and the Universe had nothing to do with what we thought it did.

But that could be the EtOH talking.
Norm.

Thanks for all your replies. I guess I’ll have to get the book to really grok it (to the extent it can be understood). Based on your descriptions strings seem to be proposed “real” one dimensional points (how the hell is that possible?) composing the sub-quantum ether through which all forces and time mediate and which most importantly, make the math work better, which is not in any way a trivial distinction.

All the physicists originally assumed that the particles were O-dimensional points. String theory replaced the point with a 1-dimensional line. The logic is to create a handle on the situation; a line having more mathematical structure than a point.
The framework simply lends itself better towards unification.