# What is string theory? Why was a new theory required when modern Physics was only one step away from establishing a G.U.T.? [closed]

What is string theory ? (correct me if i am wrong) Why a new underlying theory was required when modern Physics was only one step away from establishing a G.U.T. (unification attempt for four fundamental forces out of which three could be clubbed.) using Tensor Flow ?

• Some think String Theory is that one step. – S. McGrew Oct 6 '20 at 1:56
• TensorFlow as in the software library? It sounds like you may have been misinformed regarding our proximity to a GUT. – J. Murray Oct 6 '20 at 2:02
• Thanks for correcting me but yours truly can't actually call it Tensor calculus, me being so used to calling, processes of Differentiation and Integration as Calculus (as done by few other Lecturers in Indian universities also) Tensors seem to have more resemblance with Vectors and Algebra. Development of Tensors as a tool are attributed to Mr.A.Einstein who put an end to Newton's Mechanics as the "final verdict" in our understanding of Physical world. (heard that differnce equations were more prevalent in those times rather than much purer calculus that we are able to see today). – Aryan Gupta Oct 6 '20 at 3:11
• What do you mean by “clubbed”? – G. Smith Oct 6 '20 at 3:12
• The premise of your question is false. GUTs did not attempt to include gravity. They attempted to unify the strong force with the electroweak force. – G. Smith Oct 6 '20 at 3:30

In physics, string theory is a theoretical framework in which the point-like particles of particle physics are replaced by one-dimensional objects called strings. String theory describes how these strings propagate through space and interact with each other. On distance scales larger than the string scale, a string looks just like an ordinary particle, with its mass, charge, and other properties determined by the vibrational state of the string.