Ontoplankton said:
vanesch,
Well, that's what I came here to ask you guys who know more about this stuff. Are natural processes similar enough (in other ways than energy) to what happens to the LHC, that we can say that if this specific thing happens in the LHC, it happens in nature?
Yes. In the LHC won't happen any processes that don't happen already somewhere in the universe, and even on earth, the moon etc..., at least if certain very elementary principles hold, such as the principle of relativity that says that the physics is independent of the frame of motion in which it is observed, which allows us to "go to the center of mass frame".
There happen, all the time, much higher-energetic collisions between protons and nucleae around us. The main difference is that the center-of-mass of these collisions is usually at high speed with respect to, say, "the ambient fluid of matter in space" (the planets, the stars and so on). If we can "transform to the center of mass" system, then there are miriads of collisions which look exactly like those that will happen in the LHC, and often even more energetic.
Of course, if you adhere to some kind of ether theory, then you cannot say that these collisions are entirely equivalent, as they happen in reference frames which are moving with high speeds wrt the ether frame...
The particularity of the LHC collisions is that they will happen in a reference frame which is essentially at rest with the Earth (and grossly, with the "matter fluid" in space). That allows us to study them. Also, the luminosity of the beams is of course much higher than what can be found in outer space: that means, that more of these collisions happen in a smaller 4-cube of spacetime than is usually the case in outer space: in other words, the reaction rate will be much higher. That's because one wants to have the occasion to have some statistics, to have a certain number of interesting events. Otherwise, we would have to run the experiment for millions of years if we were going to have particle beam densities comparable to outer space. But there's nothing *specific* about the collisions in the LHC that doesn't happen already all the time, and all over the place, in the cosmos.
Also, you have to understand that "creating baby universes" is not something that follows "almost unavoidably" if we take standard physics at heart. It is a highly speculative idea. It's nothing that is "forced upon us" by circumstantial evidence and the theory that's built upon that.