Re: Evidence for "Big Bang Theory"

Michael White (mwhite@mitre.org)
Wed, 03 May 1995 15:42:53 -0500

> Until a theory exists how do you determine what facts must be sought to
> disprove it ? Science is the explaination not the collation of facts.

Science attempts to describe the universe in a self-consistant way. The
scientific method starts with observing a phenomenon. We then devise a
hypothesis to explain the phenomenon; that is, we make up a story about
how it might work. Then we use the hypothesis to make a prediction of
something that follows logically from the hypothesis, but that we haven't
seen yet. Then we make an experiment to see if the universe works the way
our hypothesis says it works. If so, the hypothesis is strengthened, and
we consider it a bit closer to being true. If not, we change the
hypothesis to account for the newly observed facts. With each positive
finding, we consider the hypothesis more true, until after a while, we
consider it so true that we call it a law.

Opinion and personal convictions have no place in the scientific method.
It is a purely objective means of testing the truth of hypotheses. No
amount of belief or wishful thinking ever made a fact. The universe is
what it is regardless of what people think or don't think, say or don't
say, about it. It is the job of science to describe that universe.

In the case of the big bang, the observation was that nearly everything in
the universe is flying apart. The hypothesis was that the universe was
created in a hugh explosion of space, time, energy and matter around 10 -
15 billion years ago. The prediction was that if such an explosion had
occured that long ago, we should still be able to detect energy left over
from it, at about 3 degrees Kelvin. The test was to listen for that energy
with a radio telescope. The result was that the energy was there, exactly
as the hypothesis predicted. Therefore, the credibility of the hypothesis
was enhanced. More recently, the hypothesis was in trouble because more
careful analysis revealed that the background radiation should be less
uniform, and more lumpy, than it seemed to be. Everyone thought that we
might have to change the theory to account for the smoothness. But NASA's
COBE satellite, by far the most sensitive instrument for this purpose to
date, detected exactly the kind of lumpiness in the background radiation
the hypothesis predicted. So once again, the credibility of the big bang
hypothesis was enhanced. The Big Bang was shown to be an effective and
comprehensive description of the universe as we observed it. If in the
future, facts come to light that are not consistant with Big Bang, we
might have to alter or discard the theory. Something like that is
happening right now, as recent measurements suggest that the universe is
younger than some of the stars in it. Cleary this is impossible, so
everyone is carefully examining both the hypothesis and the data.

Note:
It turns out that you can actually see the big bang on your TV set, if
it's hooked up to an antenna (not cable). Tune to an empty channel; you
see snow. Turn the brightness down until the screen is covered with
discrete flecks of light. About one out of every 20 flecks of light is
energy left over from the big bang. Pretty cool, I think.

-- 

mwhite@mitre.org



My opinions are my own, not my employer's.