I must admit that during the last few years (as I was always very busy working in this period) I haven’t have the time to follow the recent advances in physics and astronomy (as I used to do in the past, reading related news and articles). But I got back to such issues as a few days ago when I watched a nice show on Discovery Channel regaring the Hubble Telescope and its close end of life time. Beside other interesting things, they have also presented information about the dark energy and about some other universe related concepts, that immediately gained back my interest. I warned myself: it seems I have been missing important discoveries lately!
And therefore, I was eager to find out more about these recent scientific discoveries and the theories proposed behind them. I have read some articles on the Web, such as items in Britannica, Encarta (available only until Oct. 31), and Wikipedia encylopedias, but I became a little sad afterwards because it’s clear now: our current understanding of physics is still so limited and not close at all to a unified theory about everything in the universe!
It seems that dark enegery makes our universe expand faster than expected, and therefore the universe will probably expand forever, to an infinite volume, decreasing matter density. All particles will finally get to their end because all links between them would be destroyed. The end of the universe will therefore be not the big crunch, but a maximum possible entropy level.
Of course, these recent discoveries are one step closer to the truth, but they are also a warning to us: we will never be sure of a unified theory, even if we find it. Maybe such a theory exists, but people couldn’t ever be sure about it, as we all live inside the universe itself and we can do only a finite number of internal, “local to our existence” tests. Each such successful test would confirm the theory but will never prove it, as any future failed test would negate the theory for good.
Anyway, based on the new information, I think that the general relativity theory may be only a subset or approximation of the unified theory that we are searching for, just as Newton’s gravity law was only an approximation of Einstein’s general relativity. I also think that eventually no cosmological constant would be needed in the universe model, and further more, I think Stephen Hawking’s idea of a universe model that doesn’t require a creator (having the big bang, black holes, and/or the maximum possible entropy level as natural states of the space-time, and not exceptional events) is still on and acceptable. But I’ll let the sciencist do their jobs and confirm or infirm my guess! (Hopefully I would have more time to follow them in the future!)