Any idea ?

[sapiensvsapiens]

Any idea about, ekyprotic and inflation has to be unified in a way? Or they will have to build smt different?

[sapiensvsapiens]

Am I invisible ?

sapiens

[PhysBrain]

No, you're not invisible, just not understood. Could you please provide some more context and explanation for the question you're trying to ask. I have a fairly decent background in astrophysics, but I have no idea what you are talking about. I apologize for being too lazy to go out and look up ekyprotic, and smt different, but I think that others on this board might also like an explanation of these terms. Thanks.

[PhysBrain]

Ok, since inquiring minds (mostly mine) want to know, I was able to dig up the following information which may help shed some light onto the question sapiensvsapiens was trying to ask. Keep in mind that I am not a cosmologist, and the information in this post has been gathered almost exclusively from the web.

The subject is cosmology. The topic is the origin of the universe. There are two theories that attempt to explain what went on before the big bang. These theories try to describe what the universe was like at a time when Einstein's general relativity theory breaks down due to the incredibly small dimensions of the universe at its very beginning.

The first theory, called inflation, is based on quantum gravity theory. The second theory, called ekpyrotic, is based on String/M-Theory (SMT). Inflation theory is currently the favored theory among most cosmologists. But since one of the principle goals of string theory was to incorporate quantum gravity into a consistent theoretical framework with the rest of the fundamental forces of nature, string theorists figured that there had to be a corresponding model for inflation that is consistent with SMT.

The inflation model is based on some fortuitous quantum mechanical fluctuations that created what they call a false vacuum. The false vacuum is characterized by a highly repulsive gravitational field. The space time created in the false vacuum exploded exponentially until it cooled enough for the initial quark soup to form at the beginning of the big bang.

The ekpyrotic model changes the causal factors a little bit. In SMT, our universe exists within a 5D space (actually 11, but 6 of those dimensions are rolled up into a ball so small that is practically imperceptible to us). The so-called visable universe is one of two 3D "surfaces" enclosing a 4D volume within this 5D space. If a 5D soliton gravitational wave were to impact the 3D surface which is our universe, then the imparted energy could, in theory, account for the expansion and composition of our observed universe.

Now, to attempt to answer the question put forth by sapiensvsapiens. Ekpyrotic and inflation theories are not necessarally mutually exclusive. The fundamental assumptions posed by each are somewhat different, but they are both attempting to provide a description for what circumstances could have possibly lead to the creation of a universe such as ours. I read in a thread somewhere ( http://superstringtheory.com/forum/stringboard/messages13/140.html ) that a theorist by the name of Linde, who initially criticized the ekpyrotic model, has recently tried to modify the model to bring it closer to compatibility with the inflation model.

As I said, I am not a cosmologist, but this brief description is what I have been able to comprehend in less than a week of searching on the web. If anyone out there has any further insights (or corrections), please feel free to post them here.

If anyone is seriously interested in string theory, I encourage you to go to the web site: http://www.superstringtheory.com/ for more information.