Re: Accuracy of the big bang theory

Hi Jeff,
Yes, the Big Bang theory is "only a theory", but that's true of every scientific idea [in the sense in which you have used "theory."] The most important principle of science is that all ideas should be constantly tested, by comparing with observations and experiments. Every scientific idea can be changed if the facts prove it wrong or incomplete. So far, the Big Bang theory has always agreed with experiments and observation, and seems like a very good theory, at least after the first microsecond or two. Why try to push back further, and understand times earlier than that? Because we're curious. Scientists are always trying to understand as much as we can, and the first fraction of a microsecond after the Big Bang is just one more puzzle we'd like to figure out. Sometimes figuring out the puzzles is useful (leading to medical cures, or better technology, or inventions or whatever) and sometimes it's just for fun. Usually you can't tell until after you solve the puzzle whether or not it will be useful.

I'm not sure what you mean by "Since the big bang has never been modeled". The Big Bang theory is a model of how our Universe began. It has been studied and modelled in computers and on paper and in peoples' brains many times in many ways. Of course, no one has been able to build a new Universe to test it out, but we have done lots of experiments and measurements to test the models.

You can read more about the Big Bang and cosmology in lots of places on the Web (including the Mad Scientist archives). You didn't say what your grade level is, so I don't know whether you'd be interested in advanced discussions or more introductory stuff but here are a few interesting sites:

• http://map.gsfc.nasa.gov/html /web_site.html

• http://cassfos01.ucsd.e du/public/tutorial/BB.html

• http ://www.vuw.ac.nz/~mackie/royal_society/nzst_article/universe.htm

I hope this helps. Please feel free to E-mail me (stevenlevin@we.mediaone.net) if you have more questions about this.
-Steve Levin

[Moderator note: In everyday language "theory" is often used to mean an idea, possibly a wild one. In science "theory" has a specific meaning. It is a well-tested idea. Few ideas survive the observational or experimental tests required to be considered a theory. Thus, in science, calling an idea a "theory" is quite high praise.]