Scientists keep hammering on the Big Bang theory like it is some kind of divine truth. It's only a theory, so why not give it up and find something else that fits the data better?

Whoah...Just a minute there!!! Who says that 'scientists' are treating the Big Bang theory like it is a divine truth? First of all, the only scientists who have any vote in the matter are physicists and astronomers. Only they devote a sizeable fraction of their time, professional skills and reputations towards making the necessary observations, and refining theories of the physical world. Everyone else is a sideliner, or back seat driver, totally irrelevant to articulating what is, or what is not, Big Bang Theory. So, if some other 'scientist' like a biologist, a chemist, or a botanist, tells you that any astronomical theory is hooey, just remember that they are not competent to make that judgement. Would you want a archeologist to represent you in court? I don't care what credentials they might have. If they haven't worked in the field of physics and astronomy, published their ideas in refereed journals, and put their time into defending their ideas using established methods of observation and mathematical logic, they are not competent to voice either a favorable or unfavorable vote on cosmology.

Astronomers and physicists are certainly not treating Big Bang cosmology like a religious Truth. Why should they? Could you imagine how famous an astronomer would be if he/she found irrefutable proof that a major prediction ( or assumption) in Big Bang cosmology is not supported by observation? A search through the refereed scientific literature reveals dozens of variants on Big Bang cosmology, and a goodly number of anti-Big Bang theories. The central problem with virtually all of these carefully-crafted 'alternate' cosmologies is that they begin by making assertions like "Given that Einstein's theory of General Relativity is wrong" or "Given that atoms and light gain mass over the course of billions of years...", or even "Let's suppose that gravity is not the dominant force in the universe, but electromagnetism is". Those who are trying to formulate radical departures from Big Bang theory almost always have to go to enormous extremes to craft their models. At the present time, no one has yet created a competing cosmology to Big Bang theory that: 1) Is consistent with all available observational data to at least the same extent that Big Bang Theory is; 2) Doesn't ask us to violate previously-established laws of physics that have been corroborated by independent investigations; 3) Is developed by individuals who have a proven track record in developing new ideas that work.

Scientific progress is not a free-for-all where all ideas are equally credible, and all theories deserve equal weight and respect. Science is not a democratic process. If a theory isn't supported by the preponderance of the data, it doesn't matter how many Nobel Lauriats support it. The theory is a bad theory in need of revision, expansion, or outright rejection. The testing of a theory is not, however, like some court of law where a single contrary piece of evidence is all it takes to destroy the prosecution's case. This is the part that the general public and philosophers of science don't fully understand. No observation is etched in stone. Experimenters make mistakes in their labs, and at the telescope, in a variety of different ways from calibration errors to simple computational errors. It is not a good idea to throw out a theory that has worked well in the past just because a single new piece of information does not corroborate the theory. Instead, astronomers test a theory by asking it to make predictions for a number of different situations that ought to be covered by the theory. We then test all of these predictions in a number of independent ways, and by many different observers. If the process takes 50 years, who cares?

As for the Big Bang Theory, it is NOT only a theory, it's the ONLY theory we have right now that has shown time and time again that it meshes beautifully with seemingly unrelated observations. Did you know, for example, that Big Bang theory provides a logical connection between 1) the expansion rate of the universe, 2) the abundance of Lithium in the universe, and 3) the number of families of neutrinos? The current difficulty with the age problem between globular cluster stars, and the expansion age of the universe ( the stars seem older than the universe), is as much an annoyance for the folks that determine the ages of stars, as it is for Big Bang Theory. We don't yet know which area is at fault: Stellar Evolution theory, or Big Bang cosmology. Both areas of inquiry are fraught with problems in converting a set of observations into a quantity like age. The list of data and observations that are knit by Big Bang theory into a logically self-consistent story of our universe, is not just impressive, but awesome, and is second only to Darwin's 'theory' of evolution in its scope and beauty.

For some reason, perhaps fostered by the 'lets give equal time to every idea' philosophy in news reporting, many of you might believe that there are lots of data that already refute the Big Bang Theory, and that scientists are just being narrow-minded and stubborn about getting rid of the theory and starting over. As we all know, news stories sometimes get reported this way. Even though 99 percent of the vote favors one idea, a reporter will write about the majority view and that 1% fringe, giving equal space to both views. This makes it look like the ideas are shared nearly 50/50 between the two groups. The situation in astronomy with respect to Big Bang Theory is that there are some discrepant predictions that don't seem to match up with observation. The age problem is a key, and pretty major, problem.

A glance at the literature shows there are plenty of astronomers who are actively engaged in disproving Big Bang theory by going out there to their telescopes on an almost nightly basis, and making the necessary tedious observations. Dr. Geller and Dr. Huchra at the Center for Astrophysics in Cambridge Massachusetts have been mapping the locations of thousands of galaxies during the last 15 years, and their exciting work suggests that our portion of the universe is a lot lumpier than Big Bang theory would like to see. On the other hand, they have only mapped less than 1% of the visible universe, and it is hard to disprove a theory when you only have 1% of the necessary data!! The COBE observations, on the other hand, are fully supportive of Big Bang cosmology, augmented perhaps by an inflationary phase in its early history.

The bottom line is that Big Bang is not massively broken, and the observations we need to come to some better judgment about its details are still a decade or two away. What is Dark Matter? Is there a non-zero Cosmological Constant? Hubble Space Telescope's careful analysis of the motions of one or two galaxies is NOT sufficient evidence to demonstrate a problem with Big Bang theory. Many more galaxies will have to be studied to make certain that our little 1% corner of the universe isn't some deviant region sitting on top of a much larger distribution of matter ( or dark matter!) which is behaving in a way consistent with Big Bang theory. The testing of a theory is not like the testing of guilt or innocence in a court of law. Every observation is fraught with error and uncertainty, and only by comparing a variety of predictions against a host of seemingly unrelated data can a true test be performed.

Copyright 1997 Dr. Sten Odenwald
Return to Astronomy Cafe.