What's string theory???

Answer 1

It is an attempt to describe the universe at an extremely small scale. It suggests that atoms are made up of particles called quarks which consist of vibrating strings.

Answer 2

It's the Theory of Everything. Just as everything in the Universe is made of atoms, electons, neutrons, protons, quarks, etc...a string is what you get when you finish deducing everything down to the smallest element. Therefore it's the smallest thing in existence. It's what connects everything. I think it comes from the the theory that the Universe has 11 dimensions. In the eleventh dimension there are membranes that rub up against each other. That's how our Universe was formed. Two of the membranes rubbed up against each other and caused the Big Bang (I'd rather call it the Big Expansion). Once that happened, Superstings came on the scene and then space and time as we know it evolved from that.

Answer 3

Difficult.

It hinges on the concept that every subatomic particle isn't truly a particle, but a sub-sub-atomic (we're talking REALLY tiny here) string that vibrates with different energies and frequencies. Different modes of vibration manifest themselves as different particles.
Some theories have open ended string, others closed. Some require 13 dimensions, some (though I think now discarded, maybe - I'm sure someone can correct me) up to 26 dimensions.

It appears that, whereas quantum mechanics is irreconcilable with general relativistic gravity, gravity is actually a by-product of string theory. However you formulate it to be consistent with QM, gravity comes free!

However, some have questioned the scientific validity of string theory on the grounds that, as the strings themselves are so small it's impossible to verify their existence by experiment and thereby validate the theory, in accordance with scientific practise. One then gets into the philosophical argument of scientific rigour and reality.

That aside, it remains a remarkable mathematical construct.

Answer 4

String theory is a model of fundamental physics whose building blocks are one-dimensional extended objects (strings) rather than the zero-dimensional points (particles) that are the basis of the Standard Model of particle physics. For this reason, string theories are able to avoid problems associated with the presence of point-like particles in theories of physics, in particular the problem of defining a sensible quantum theory of gravity. Studies of string theories have revealed that they predict not just strings, but also higher-dimensional objects.

The basic idea behind all string theories is that the fundamental constituents of reality are strings of extremely small scale (possibly Planck length, about 10-35 m) which vibrate at specific resonant frequencies. Thus, any particle should be thought of as a tiny vibrating object, rather than as a point. This object can vibrate in different modes (just like a guitar string can produce different notes), with every mode appearing as a different particle (electron, photon etc.). Strings can split and combine, which would appear as particles emitting and absorbing other particles, presumably giving rise to the known interactions between particles.

In addition to strings, string theories also include objects of higher dimensions, such as D-branes and NS-branes. Furthermore, all string theories predict the existence of degrees of freedom which are usually described as extra dimensions. String theory is thought to include some 10, 11 or 26 dimensions, depending on the specific theory and on the point of view.

Interest in string theory is driven largely by the hope that it will prove to be a consistent theory of quantum gravity or even a theory of everything. It can also naturally describe interactions similar to electromagnetism and the other forces of nature. Superstring theories include fermions, the building blocks of matter, and incorporate supersymmetry, a conjectured (but unobserved) symmetry of nature. It is not yet known whether string theory will be able to describe a universe with the precise collection of forces and particles that is observed, nor how much freedom the theory allows to choose those details.

String theory as a whole has not yet made falsifiable predictions that would allow it to be experimentally tested, though various planned observations and experiments could confirm some essential aspects of the theory, such as supersymmetry and extra dimensions. In addition, the full theory is not yet understood. For example, the theory does not yet have a satisfactory definition outside of perturbation theory; the quantum mechanics of branes (higher dimensional objects than strings) is not understood; the behavior of string theory in cosmological settings (time-dependent backgrounds) is still being worked out; finally, the principle by which string theory selects its vacuum state is a hotly contested topic (see string theory landscape).

String theory is thought to be a certain limit of another, more profound theory - M-theory - which is only partly defined and is not well understood.

A key consequence of the theory is that there is no obvious operational way to probe distances shorter than the string length.

Answer 5

It is the unified theory of the universe estimating that fundamental ingredients of nature are not zero-dimensional point particles but tiny one-dimensional filaments called strings.

String theory harmoniously unites quantum mechanics and general relativity, the previously known laws of the small and the large, that are otherwise incompatible. Often short for superstring theory.

Answer 6

A theory that everything is made up of tiny rubber band like strings, these strings make up the sub-atomic particles (protons, neutrons, and electrons). Its all part of quantum physics/mechanics. type string theory into google there are many sites that describe it.

Answer 7

In the most simplist terms possible its the latest theory by todays top scientist that string theory is the theory of everything. They attempt to connect everything in the universe as one. String theory theorizes that within the universe there are 11 dimensions and that everyone of these dimensions are connected.

Answer 8

string theory hmmm!!! i can only tell you that it is a very recent developement in physics where they are trying to say that the world is made up of strings which are very thin instead of atoms.

Answer 9

just another theory of evolution, like darwin's theory of survival of the fittest

Answer 10

I've learned something new today.

Thanks people.