For The Love Of Science

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Comment by Dr Manhatten on September 26, 2012 at 4:06pm

Einstein was among the earliest to propose that such a unified field theory must exist, and he struggled -- without success -- for most of his later life to find the right theory. Today we may be on the verge of realising Einstein's dream. String theory is currently the most promising example of a candidate unified theory. We are not yet sure that it correctly describes nature, but it broadly describes a world similar to ours, and is endowed with beauty and consistency to an astonishing degree.

       

       The physical idea is utterly simple. Instead of many types of elementary point-like particles, we postulate that in nature there is a single variety of string-like object. The string is not ``made up of anything'', rather, it is basic and other things are made up of it. As with musical strings, this basic string can vibrate, and each vibrational mode can be viewed as a point-like elementary particle, just as the modes of a musical string are perceived as distinct notes!

       Thus string theory certainly is a model of elementary particles. The great surprise is that mathematical equations describing strings are highly constrained by consistency. In some sense, most of the equations we would think of writing down turn out to be inconsistent, only a few appear to be allowed. Indeed, it looks most likely that (unlike particle theories) there is only one unique string theory! If so, what does it predict, and is it the promised unified theory?

       Besides these surprises, there are many others that we have stumbled upon in the last decade. In string theory, the fact that there are three space dimensions in our world might also be predicted rather than assumed. The dimension of ``space-time'' is variable in string theory, in the sense that we have to understand and solve string equations to determine it. This has not been done yet, because of the great complexity of the theory. If the answer comes out to be four (three space and one time) then we would have ``explained'' one of the most deep and abiding mysteries since the dawn of civilization: why does our world have the dimensionality that it has? If the answer is something else then string theory may be the wrong theory of nature, though we may still learn something about the right theory. Only successful comparison with experiment can give us convincing proof that string theory is correct.

Comment by lazyraven on March 31, 2012 at 5:42pm

i am a fan of quantum physics. the study of possibilities. intent and conscienceness can change the molecular structure of anything.