| Part 3:
The problem was that there wasn’t one version of string theory, in fact there were five versions of string theory. All involving strings however all with what seemed like very different math. This may have seemed good to some people; the optimist would have said that well now we just have more theories that could lead to the theory of everything, greater odds of success. However to most physicists it was, well, embarrassing. How could there be five versions. The problem was solved by what may be Einstein’s successor, Ed Witten. Ed Witten wanted to do something special for the annual conference of string theorists in 1995 at the University of Southern California, so he decided to eliminate some of the string theories. When he actually went to the meeting he announced that he had solved the problem of the multiple theories and presented a solution that basically said that the other string theories were just kinds of reflections of each other. He basically looked at the problem from a different perspective and incorporating all of the theories M-Theory was born. The M part of M-theory seems to be a somewhat of a mystery. Some think it is an upside down W for Witten, however Witten explains that the M stands for Magic, Mystery, or Matrix depending upon which you prefer. He also has been rumored to call it Murky because he stated that the understanding of string theory right now is so feeble. M-Theory was a massive success for string theorists, they now had eliminated one of the major problems, it was almost as it had re-sparked interest in the topic and everyone wanted to keep up with this new development. M-theory however changed the 10 dimensions needed for the old models and added one more dimension to make the grand total of 6 dimensions. M-theory also allowed for some other spectacular ideas. One was that strings could stretch to the size of say a universe or greater into something called a membrane, or brane for short. M-Theory also inferred that we, our entire universe, be living on a membrane that is in higher dimensional space, next to many parallel universes. It would be like we were a slice of bread on a bigger thing that physicists like to refer to as the bulk. This could mean that there could be parallel universe next to us in the other dimensions of space less than a mm away, it’s just since it would be in other dimensions and we are trapped in ours that we can never touch it. However if this is true this means that are perception of the universe is limited by what we experience in our universe where we are on the brane. It very will could be that these other universe could be similar to ours having planets and maybe some sort of beings or it could be that these universes be completely different from ours ruled by entirely different laws of physics. However living on a brane may explain something that has puzzled scientists for a long time. Why the hell is gravity so weak compared to the other forces. I mean it is a thousand billion billion billion billion times weaker than even electromagnetism. In fact I am able to lift this up (pencil or some object), overcoming the entire planets gravitational pull. Is this because I am super human, no it’s because although gravity may seem very strong it is actually incredibility weak compared to the other forces. If you need another example just grab a magnet and have it pull something up, again a small magnet versus the entire planet’s pull and the magnet will win. So how does the weakness of gravity have to do with the idea of the universe being trapped on a brane. Well the answer lies on the differences in dimensions. Lets for simplictic sakes reduce our universe to 2 dimensions and the brane to 3 dimensions. In this aspect we can go back and forth and side to side but never up and down. It is theorized that M-theory would require instead of only closed loop strings that the loops have endpoints that are connected to the brane. However there would still exist some closed loop strings and one idea of what a closed loop string would be would be the graviton, the theorized particle that would be responsible for gravity. It may be weird to think of gravity working because of a force particle but all the other forces work by using force particles. The force particle for the strong forces is the Gluon, for the electromagnetic force is the photon, and for the Weak forces it is the weak gauge boson. So even if gravity has a force particle, how does it explain why gravity is so weak? It explains why gravity is so week because of the idea that it would be a closed loop string. Instead being attached to the brane and limited by our dimensions it could be free to travel into the other dimensions, thereby in a sense disappearing from our dimension. In this fashion the reason gravity is so weak is because it quickly moves out of our universe and into others. However this in a fact leads to another possibility. If in fact string theory is true and we do live on a brane with parallel universes than why would it be hard to imagine that there is life in these parallel universes, and hypothetically if there was life on these parallel universes why would it be hard to imagine that they are close to us in intelligence. Then although we could never see each other it would be possible to communicate with each other through strong gravity wave sources. The brane theory also offers a new model to the idea of the creation of the universe. It basically says that if there is one brane then there must be other branes out there, and if they are what would happen if the two branes collided. Some now believe that this may have been the even that triggered the big bang, however his has two major implications. First of all it means that the creation of the universe was nothing special and things like this happen all the time. And Secondly that we are currently on a crash course with another brane. However this theory is highly controversial even amount string theorists. The thing that is unique about this theory of the big bang is that it finally allows for something that would have triggered the bang as compared to most theories which trace back towards right after the bang, but don’t include anything on what actually caused the bang. However something all string theorists agree on is that String Theory needs to provide evidence of it being correct, otherwise if it can’t no one should believe it. If there is no evidence that can help prove string theory than many feel it is not a theory of physics, rather a theory of philosophy. This may at first glance seem very hard to do since strings are so close to Planck’s length in size that they will probably never be able to be viewed directly. However if strings were around at the beginning of the universe than we may one day be able to find evidence of strings in space, as any “evidence” or traces strings left in the beginning of the universe would have been stretched out and enlarged. There is also hope that we will be able to find evidence for string theory here on earth using powerful atom smashers. The folks at Fermi lab and in a few years CERN will be looking for many things that could help provide evidence for string theory. There is also hope that the atom smashers could show the existence of something called sparticles which would show evidence for something called supersymetry. Supersymetry is something that predicts extremely much heavier particles for things such as electrons, protons, and even gravitons. The problem is that they would be so heavy that the current detectors may not notice them, and so far no one has found any evidence of their existence. However since string theory predicts their existence it would provide strong evidence for string theory. However probably the best way to provide evidence for string theory would be if they could find a graviton, at its moment of disappearance when it would be moving into other dimensions, not only would this prove the existence of the graviton but it could also explain things such as why gravity is so weak. So in all reality when do we know if string theory is real or not? The truth is no one knows, one thing is for sure, with the creation of the new atom smashers like CERN over the next 10 to 20 years the way we view the universe is likely to change, whether or not it predicts string theory to be true or not, no one knows. However for the sake of the grail, many hope that it does.  |