String theory provides the idea that the fundamental building blocks of the universe are very small pieces of vibrating string with the different atomic particles corresponding to different vibrational states of the string. It is not clear at present whether the idea is true or not, though it has been around for some time.
There are various string theories requiring 26 space-time dimensions, or 10 dimensions for superstrings, and 11 for M-Theory, where the additional dimensions are “compactified” or hidden in some way. In the latter case we have the concept of a brane, a higher dimensional string, which has been used recently to suggest a new type of cyclic universe. Therefore there should be no problem as to how it is that we could know something about them.
Support for the idea of a big bang comes from the fact that the universe is expanding outwards at a very high speed and if the motion of the galaxies is traced backward in time they all merge together at some time in the past. Einstein could not provide an explanation of his theory that would not require a beginning or a Beginner and later wrote of his desire “to know how God created the universe.”