Re: Missing Mass (was Re: Big Bang: How widely accepted?)

Allan K Richardson (
7 Sep 1995 06:35:41 GMT

Andrew J. Sutter (you@somehost.somedomain) wrote:
: I thought the missing mass question wasn't essential to the Big Bang
: hypothesis, but only to the question of whether the universe will
: expand indefinitely or collapse back on itself sometime in the future.

: I suppose another use for the missing mass is to explain much more
: local things like weird galactic rotation curves (i.e., where the
: galaxy rotates as if it had a lot more mass in its disk than appears
: to be glowing).

As I understand it, rotation curves, etc., are the stronger motivation,
with the effect on omega, the expansion parameter, to follow, depending
on how much 'missing mass/dark matter' one supposes there to be. Of
course aesthetic biases (like 'gee, I'd like omega to be 1') will point
one in certain directions.

: Is this correct? If so, the cosmological aspects of the "problem" of
: "missing" mass seem to me a bogus one -- it simply results from the
: aesthetics of cosmologists, who seem dissatisfied with the notion
: that there just isn't enough mass to prevent indefinite expansion
: (if the rest of their hypotheses are correct). Even scientists can
: create myths without being aware that they're doing so.

Well, in the sense that the existance/amount of missing mass will affect
our understanding of the rotation curves, etc., and omega, one could
hardly call the cosmological significance 'bogus'. After all, these are
very much a part of cosmology.

On the other hand, I imagine you may have meant something like 'the
notion that the idea of missing mass affects the validity of the big bang
hypothesis seems bogus'. In this sense I think we would need a better
idea of how much of the stuff there is and, more importantly, just what
the hell it is, before we could address questions like "can the missing
mass be reconciled with the big bang?"

As a caveat, I must add that I have spent most of my time in the quantum
world, dealing with matter-free models, so....heck, what do I know?


**Why is my radio lifting off?**