## What are the characteristics of string in string theory?

According to the theory, the strings are so small that they appear to be points—as particles had long been thought to be—but in reality they have length (about 10−33 cm); the mass and charge of a particle is determined by how a string vibrates.

**What are the string theory dimensions?**

Current versions of string theory require 10 dimensions total, while an even more hypothetical über-string theory known as M-theory requires 11. But when we look around the universe, we only ever see the usual three spatial dimensions plus the dimension of time.

### Can string theory explain black holes?

In string theory, black holes are neither black nor holes. Instead, the best metaphor to explain what a fuzzball is to look at another compact-and-weird object in the universe: neutron stars. Neutron stars are what happens when an object doesn’t quite have enough gravity to compress into what we call a black hole.

**Why does string theory need 10 dimensions?**

String theory requires 10 dimensions because it doesn’t work in any other number of dimensions. Roughly speaking, the problem is that the classical string has a certain very important symmetry, and this symmetry is broken when you try to describe a quantum string.

#### What is the significance of two dimensional theory in string theory?

Also, two dimensional conformal ﬁeld theories provide the dynamical variable in string theory. In this context, conformal invariance turns out to give constraints on the allowed spacetime dimension, i.e. it restricts the central charge of the Virasoro algebra c, and the possible internal degrees of freedom.

**What are some criticisms of string theory?**

Initially people took this to be a criticism of string theory. If it predicts 10 dimensions and you look around and only see four (three spatial dimensions and one time dimensions) then you might ask: “Where are the other six dimensions?” But Kaluza and Klein had solved that problem 60 years earlier: they rolled the other dimensions up.

## What are the different types of string theories?

The developements include scattering theory, BRST quantization and BRST coho- mology theory along with RNS superstring theories, dualities and D-branes, eﬀective actions and M-theory and then ﬁnally matrix theory. – 10 – 2. The Bosonic String Action

**How long is a string of string theory?**

In theories of particle physics based on string theory, the characteristic length scale of strings is assumed to be on the order of the Planck length, or 10−35 meters, the scale at which the effects of quantum gravity are believed to become significant.