What is the string theory?

Answer 1

String theory (also known as 'M' theory) is a purely mathematical system constructed with the purpose of fulfilling the goal of uniting all four of the fundamental forces of nature into what's commonly called the Grand Unified Theory (GUT). One of the revolutionary concepts inherent to string theory is that the family of sub-atomic particles (protons, electrons, neutrons, etc.,.) are the result of infinitely tiny vibrating "strings," with the type of particle being determined by the frequency/wavelength of the string that causes it.

Answer 2

The answers so far are all correct, but I felt compelled to interject my opinion of it.

What is string theory? Its crap.

We have 2 theories that can explain virtually everything, but fundamentally can't be meshed together. String theory attempts to do this as it's outright goal, and doesn't try to explain anything new (like any good theory should). It's just after a workable model to link the two.

I see it as something akin to to those who tried to add the aether to Newtonian mechanics in an attempt to explain the speed of light. Just people making up bs because they don't know what the real problem is. The difference is where Michelson & Morely could devise an experiment to disprove the aether, doing something similar for string theory is REALLY friggin hard because it is essentially BUILT in order to avoid that.

I just felt you needed that side of the story too.

Believe what you want.

Answer 3

String theory is an attempt to unify General Relativity and quantum mechanics. String theory states that all objects in the universe are manifestations of energy strings which vibrate at different frequencies. According to the theory, it is these various vibrations that give rise to the differences in fundamental particles.

Answer 4

That is a huge question. In the simplest terms I can think of, it is an attempt at a unifying theory for the universe. There are laws governing the subatomic particles (quantum theory) and laws governing the larger world and universe we see around us (general relativity) but they don't mesh. String theory is one way that physicists are trying to tie those two world views together.

Answer 5

Think of a guitar string that has been tuned by stretching the string under tension across the guitar. Depending on how the string is plucked and how much tension is in the string, different musical notes will be created by the string. These musical notes could be said to be excitation modes of that guitar string under tension.
In a similar manner, in string theory, the elementary particles we observe in particle accelerators could be thought of as the "musical notes" or excitation modes of elementary strings.
In string theory, as in guitar playing, the string must be stretched under tension in order to become excited. However, the strings in string theory are floating in spacetime, they aren't tied down to a guitar. Nonetheless, they have tension. The string tension in string theory is denoted by the quantity 1/(2 p a'), where a' is pronounced "alpha prime"and is equal to the square of the string length scale.
If string theory is to be a theory of quantum gravity, then the average size of a string should be somewhere near the length scale of quantum gravity, called the Planck length, which is about 10-33 centimeters, or about a millionth of a billionth of a billionth of a billionth of a centimeter. Unfortunately, this means that strings are way too small to see by current or expected particle physics technology (or financing!!) and so string theorists must devise more clever methods to test the theory than just looking for little strings in particle experiments.
String theories are classified according to whether or not the strings are required to be closed loops, and whether or not the particle spectrum includes fermions. In order to include fermions in string theory, there must be a special kind of symmetry called supersymmetry, which means for every boson (particle that transmits a force) there is a corresponding fermion (particle that makes up matter). So supersymmetry relates the particles that transmit forces to the particles that make up matter.
Supersymmetric partners to to currently known particles have not been observed in particle experiments, but theorists believe this is because supersymmetric particles are too massive to be detected at current accelerators. Particle accelerators could be on the verge of finding evidence for high energy supersymmetry in the next decade. Evidence for supersymmetry at high energy would be compelling evidence that string theory was a good mathematical model for Nature at the smallest distance scales.

Answer 6

An attempt to unify the Quantum Theory and the General Theory of Relativity into one Grand Unified explanation of everything.

Answer 7

Watch the PBS TV show, "The Elegant Universe". It is not a new program, but aired again the other night on my local PBS station, on the NOVA program. It is all about string theory.

Answer 8

Nothing important.