Theories of the Universe
Supersymmetry, Superpartners, and Superman
A couple of centuries from now, historians of science are going to look at the twentieth century as the point in time when science originated the central idea that the universe is in a constant state of change and is always evolving. Although this may not sound like any big deal, it does express a new way that science expresses its cosmology. Of course whether it remains this way, only time and new theories will tell. But I think it's safe to say that there won't be a return to the idea that the universe is static and unchanging. However, how and what the universe is evolving toward is another question and raises an almost unlimited number of questions. We'll come back to those questions in a few sections. I just wanted to whet your appetite.
But to get back to the original statement, that science sees the universe as changing and evolving reflects a level of confidence in the scientific paradigm that is due to the knowledge that has been brought together from the two areas of cosmology that we've been examining in the last 10 sections: the microcosm and the macrocosm. Particle physics (microcosm) and astrophysics (macrocosm) have been able to develop a better understanding of the universe because of what each has learned from the other. It's one of the reasons why I devoted a couple of sections to explaining the world of the atom. And it's the unification of these two areas of cosmology that is the Holy Grail that science seeks. For when the microcosm is united with the macrocosm, the most complete picture of the structure of the universe will have been attained, or so it is thought. The discussion in this section and the next will also be within the context of the standard model, since all the knowledge gained works from that theory.
The First Three Minutes
While it's easy to visualize the explosion of the big bang as analogous to an atom bomb, it was really much different than that. A common misconception is to think that it occurred at a specific point in space, but there was no space for it to explode into. It's much more like blowing up a balloon. The space inside continues to expand the more air you blow into it. And that's what the expansion of the universe was like. It wasn't expanding into space that was already there. It was creating space and time as it expanded. There was and is no physical object that exists outside of the space/time created by the big bang.
To understand the search for the ultimate theory (or as you already know, the TOE), we need to know what already has been accomplished. This won't take very long, just the first three minutes of the creation of the universe. It is during this period of time that the microcosmic forces that shape our universe today had their origin. Given the point in time where we are now, physicists can mathematically calculate the expansion of the universe in reverse. It's how they've been able to estimate how old the universe is. It also provides a way to restructure the universe to the point of the big bang. From that beginning, it is then possible to work forward again and see how the universe unfolded.
By the time the universe was just three minutes old, the four fundamental forces were already in existence and the basic building blocks for helium and hydrogen, the two elements that make up 99 percent of all visible matter, were present. The key feature of the explosion of the big bang was heat. For it was only after the universe began to cool that the forces and particles began to differentiate. And we're talking 1032 degrees. Temperatures so hot that nothing that exists today even comes close. It's one of the difficulties in trying to recreate the conditions under which the four forces separated and particles came into existence. One of the uses of particle accelerators is to try to get as close as possible to the energy in these early moments as possible. But accelerators would have to be built that are trillions of times more powerful than anything we currently have to match these conditions. However, they have provided some of the initial conditions from which further knowledge of the early universe can be extrapolated.
Excerpted from The Complete Idiot's Guide to Theories of the Universe © 2001 by Gary F. Moring. All rights reserved including the right of reproduction in whole or in part in any form. Used by arrangement with Alpha Books, a member of Penguin Group (USA) Inc.