A string is not made up of anything- it's elementary. This is the main assumption of superstring theory. Superstring theory is part of M-theory. Superstring theory deals with one dimensional strings. M-theory is a general theory which deals with higher dimensional strings and also subatomic particles need not be strings, they can take on different shapes such as blobs, nuggets, or frisbees. The beauty about string theory is the harmonious marriage between Einstein's general theory of relativity and quantum mechanics. The general theory of relativity deals with massive objects such as galaxies while quantum mechanics deals with the molecular/atomic realm. A black hole forms when a star runs out of fuel, thus, it cannot generate the radiation pressure in order to balance the gravitational pull of the matter and, therefore, resulting in gravity winning the contest causing all the mass to be crushed into a single point called a singularity(the gravitational pull is so immense, even light cannot escape). At this point Einstein's general theory of relativity breaks down( that is quantum fluctuations distort the curvature of spacetime). Spacetime is bent, as proposed by Einstein's general theory of relativity and was experimentally verified in 1918 by Eddington during a solar eclipse when he measured the apparent positions of the stars by looking at stars closer to the limb of the sun and verified Einstein's prediction that the star light would be deflected by 58 degrees.The sun's gravitational pull bends the light emitted from the star, and the star appears to be in a different position similar to bending sticks in water(refraction).This phenomena is known as gravitational microlensing The whole idea is based on the fact that energy and mass are identical sides of the same coin. In order to get a feel of this concept, imagine throwing a pebble gently into a pond, this will result in a smaller splash, but suppose you swing your arm and throw the pebble into the pond, this would result in a larger splash.Therefore, energy has been converted into mass. The pattern of vibration(resonant frequency) that a string executes determines properties such as mass, force, energy, and charge. A string has a very large tension(10 raised to the 39 newtons), this means that they are very energetic( it's easy to pluck a string on a violin, but it is difficult to pluck a string on a piano i.e you require more energy). The energies associated with strings are on the order of the planck energy( 10 raised to the 19 billion electron volts) or in mass units 10 raised to the 19 times the mass of a proton. Therefore, how can you compare such massive numbers to the masses of the subatomic particles determined by particle physics.The answer lies in the fact that quantum energy fluctuations are negative and hence, they cancel or reduce these large energies such that they can be compared to the masses of subatomic particles. String theory has brilliant prospects, however, its still a long journey probably a decade, as this theory relies only on mathematical approximations using perturbation theory. The complete equations are still not known.
Bibliography: The Elegant Universe by Brian Greene |
