On Sun, 2006-10-08 at 22:29, Quantum Mechanic wrote: > I though Dark Matter started out as a concept, as in "This distribution of > matter that we can't detect today would account for observations." At some > point shortly after, someone started looking for it, theorizing about what > would be undetectable or otherwise unobserved. Then the media runs with it > as "Dark Matter Stirring Up Milky Way" or some such. > > We can't discount it as out of hand yet -- remember the neutrino? The > positron? Unfortunately, scientists are in the position of imagining > possible mechanisms to account for observations, then trying to prove the > mechanism exists. Some ideas are untestable, some are quickly proved wrong. > Somewhere in the remainder should be the answer (though it may not, or may > not be possible to prove.)
Indeed, "dark matter" is a scientifically testable hypothesis, as was the neutrino and positron before it. Given a hypothesis that, say, dark matter is responsible for the rotation curves of galaxies (one of the classical reasons for the postulation of the existance of dark matter), we can put constraints on the mass distribution of dark matter in a galaxy. We can then ask questions about what effect that mass distribution would have on other features of galaxies, both static and dynamic. For instance, what effect would it have on star formation, on star cluster dynamics, on the density distribution of star clusters, on spiral arm morphology, and so on. All these predictions are amenable to observational testing. Similar considerations apply to the hypothesis that dark matter is responsible for galactic cluster dynamics. Paul _______________________________________________ Prime mailing list [email protected] http://hogranch.com/mailman/listinfo/prime
