Higher dimension------part1

In the previous article, I talked about the string theory and its role in the grand unify theory. String theory has been considered as a strong candidate of the grand unify theory. The math equations in string theory, just like those in other verified theories, are consistent. Also, the prediction of the string doesn't contradict itself. However, string theory can not be tested at the moment. Therefore, it can not be considered a comprehend theory so far. Even so, it is still a strong candidate of the grand unify theory, because its consistency in math equations and prediction.

In the string theory, the existence of 10 dimensions is described in the theory. Before the string theory predicted the 10th dimensional space, we thought that there were only four dimensions that exist in this world---- first dimension is length, second dimension is width, third dimension is depth, and the fourth dimension is time. Nowadays, people can easily imagine four dimensions. However, most of people have a hard time imagine the dimensions above the fourth dimension. To be able to imagine the higher dimensions, we must understand how the higher dimensions are added to the lower dimensions. Assume that an ant that is crawling on a newspaper is a two dimensional creature, it can only travel on the two dimensional surface. If this ant want to travel from one end to the other end of the newspaper, the fastest way is to travel a straight line across the surface of newspaper, because this ant exist in the two dimensional world. However, if we curl one end of the newspaper to the other end, this and can travel from one end to the other, without traveling through the surface of newspaper. Normally, the ant can only move on two dimension, but when the two dimensional world it exists in is curled up, the ant travel in the extra dimension, the third dimension. However, the ant can not feel the path it travel in the third dimension. It can only feel that it is traveling in a second dimensional path.

In the fourth dimension, time is a line. (It may not be straight) Every three dimensional objects in the universe are traveling in fourth dimension, but no anyone can feel the path it travel in the fourth dimension. (Just like a second dimension creature can't feel the path it travel in the third dimension) Therefore, even time is not a straight line, we still can't feel its curve. If you were a fourth dimensional creature, you would be able to see the beginning and the end of your life at the same time. Just like they are on the two ends of a tunnel.

In the fifth dimension, time is not a single line but a line that has different branches. In other world, time is a split line in fifth dimension. Our decision can influence which branches we will go.
When the fifth dimension is curled up, the sixth dimension arises. In the sixth dimension, we can travel between different branches of future without going back in time. In the fifth dimension, on the other hand, you have to go back in time first before you enter a different branch of future. If it is hard to imagine, you can think this way: In the fifth dimension, ti,e is a split line, if you are in one of the branches at the moment and you want to go to another branch, you have to go back to the conjunction of branches, and then choose a different branch to enter. It means that you have to travel back in time, and force yourself to make different decision, so that you can go to different version of future. In the sixth dimension, things are totally different. Since the sixth dimension is a curled fifth dimension. you can travel between different ends without going through the lines, which means that you don't have to go back to the conjunction, travel back in time, to go to different branch of future.