Dark Matter

[gfish]

I'm not a astrophysicist or anything, but am I the only one who finds the whole dark matter thing rather dubious? It just smells of hand-waving kludge to me. Our observations don't match our calculations, so 95% of the universe must be made of invisible matter that only interacts with the rest of us through gravity? The universe is certainly a very odd place, but I just can't get over the feeling that this is the luminiferous aether all over again.

Comments

[peteralway.livejournal.com]

I feel a whole lot better about dark matter than I do about dark energy.

And while dark matter is a pretty vague concept, at least the name suggest that it's more of a question than an answer. A reasonable shorthand for "we don't know what's there but as far as we can tell there must be something." I think if it had a fancy latin or greek name or an acronym, I'd feel more that it was a deceptive answer. If someone called it "Umbratonium," it would sound a whole lot more like someone was hiding their ignorance.

[ivy]

[laughs at "umbratonium"] Not to mention that that sounds like a really heavy atom, which could lead to all kinds of unfortunate assumptions.

[peteralway.livejournal.com]

Well other candidates are Necronium, Occultonium, and Cryptonium--I thought Umbratonium was the least loaded of the shadowy names I could come up with.

$0.01

[rigel-p.livejournal.com]

I'll second that.

"Dark matter" as I understand it is a slang term for the as yet unknown answer to the question "Why does everything really big move as if it were a lot more massive than we observe it to be?"

Planets and non-glowy stuff was a first suggestion, but doesn't account for nearly enough mass- you run in to problems where as the proposed density of cold stuff increases to fit the required mass into the required space, you start to get absorbtion and re-emission effects. (eg, the view of the (bright) center of our galaxy is visible-light dim from here due to dust in the way, but you get a big radio signal)

http://astron.berkeley.edu/~mwhite/darkmatter/dm.html has much better clue than I.

Theories as to what it actually is range from the complicated to the truly wacky, but that's normal for a new question. It takes a while to figure out what question you're asking, let alone test the answers that people come up with.