| I think in the Feb. 93 issue of Scientific | American it was mentioned that for the Big

|> I think in the Feb. 93 issue of _Scientific
|> American_ it was mentioned that for the Big 
|> Bang theory to remain plausible,
|> dark matter must exist.

As in a post regarding the 2nd law of thermodynamics, statements such
as this pique my curiosity about the legitimacy of your physics
background and education. I am genuinely interested in understanding
how you can get matters such as these so wrong, and be a person about
to recieve an undergraduate degree in physics.

The validity of the Big Bang is not predicated on the existence of dark
matter; rather, the possibility of a cyclical universe is. The Big Bang
*could* be a single, one-time event without the need for dark matter.

However, the possibility of a cyclical Universe is not the reason for
postulating dark matter. Indeed, there is actual real data/evidence that
led to the theory of dark matter. Specifically, it is because observations
of rotational dynamics of other galaxies implies significantly more matter
in the body than can be accounted for by totaling up the observable matter
that dark matter has been put forth as a posible explanation. A competing
explanation is that there are black holes at the centers of these galaxies,
thereby affecting the rotational dynamics without a visibly obvious
explanation.

Both the dark matter and black hole theories are alive and well, and it
is probable that both will wind up being at least a partial explanation for
the observations.

Dark matter has further evidence in the observed dynamics of galactic
clusters and groups. Observed relative motions imply greater mass than
can be accounted for by what is visible.

-- 
Dave Waller