My primary objection is that alternatives to dark matter seem to have been ruled out prematurely. - Edit 1
Before modification by Joel at 02/05/2011 01:30:23 AM
That's only my impression and I don't claim authority on the subject, so I could well be wrong. I'm trying not to speculate on potential causes should my impression prove accurate. I don't want to criticize scientists on the one hand for pressing radical revisions of conventional wisdom to gain a reputation by proving exotic dark matter exists, and on the other for supporting dark matter solely because it's the current conventional wisdom.
What bothers me is that there seem to be several possible but largely unexplored alternatives to "well, that's dark matter irrefutably proven then". I'm reminded of that Laplace line paraphrased as extraordinary claims requiring extraordinary evidence; positing not just neutrinos but an entire new class of matter strikes me as something requiring a bit more evidence than one anomaly can provide. Particularly given many members of the group pressing that claim reject far older and less controversial claims possessing far more evidence....
Well we've detected neutrinos and they matched up to what we'd postulated pretty well, I'm assuming you meant the neutralinos, the leading WIMP candidate. Keep in mind that neutrinos and quarks hadn't been detected when either of us were born, and the original theory is from the 60s, the main guy who formulated it, Gell-Mann, is still alive and kicking, so its not like hypothetical particle candidates haven't been regularly proposed and disposed or proven in recent decades. Black holes have been posited as early as the 1780's, Laplace actually did some work on those, extrasolar planets have been suggested for a long time too, both weren't pinned down until pretty recently either. Takes time.
It can take time, but doesn't have to take much; the neutrinos discovery took 25 years after postulation, but the quark only took four. But what I meant by the reference to neutrinos is that it's one thing to find a single predicted subatomic particle whose unique properties make it unaffected by electromagnetism and quite another to posit a whole new class of matter composing macroscopic objects five times the mass of normal matter. I'm not saying it doesn't exist or shouldn't be researched, I just don't want to rush to definitively say it does exist.
I agree that most matter meets the broad definition of dark matter; in a sense, that's my point: If we're simply talking about non-emitting non-relective normal matter, matter we can see is probably more rare than normal matter we can't, which is to say, neither of them is very exotic at all. Ultimately that was my real point in commenting initially: "Dark matter" is a phrase whose meaning seems to vary with whom you ask, and the evidence for the exotic variety is still inconclusive, so I don't want to count my chickens before they're hatched. I'm probably a little biased in favor of dark matter being a particular type of normal matter because I perceive a bias the other way.
IS it that you think the mass estimates are actually off or that they are right and we just can't see the otherwise normal matter? Because they're kinda separate for the purpose of producing supporting evidence.
What bothers me is that there seem to be several possible but largely unexplored alternatives to "well, that's dark matter irrefutably proven then". I'm reminded of that Laplace line paraphrased as extraordinary claims requiring extraordinary evidence; positing not just neutrinos but an entire new class of matter strikes me as something requiring a bit more evidence than one anomaly can provide. Particularly given many members of the group pressing that claim reject far older and less controversial claims possessing far more evidence....
Well we've detected neutrinos and they matched up to what we'd postulated pretty well, I'm assuming you meant the neutralinos, the leading WIMP candidate. Keep in mind that neutrinos and quarks hadn't been detected when either of us were born, and the original theory is from the 60s, the main guy who formulated it, Gell-Mann, is still alive and kicking, so its not like hypothetical particle candidates haven't been regularly proposed and disposed or proven in recent decades. Black holes have been posited as early as the 1780's, Laplace actually did some work on those, extrasolar planets have been suggested for a long time too, both weren't pinned down until pretty recently either. Takes time.
It can take time, but doesn't have to take much; the neutrinos discovery took 25 years after postulation, but the quark only took four. But what I meant by the reference to neutrinos is that it's one thing to find a single predicted subatomic particle whose unique properties make it unaffected by electromagnetism and quite another to posit a whole new class of matter composing macroscopic objects five times the mass of normal matter. I'm not saying it doesn't exist or shouldn't be researched, I just don't want to rush to definitively say it does exist.
Anyway, I'm not sure who is saying "well, that's dark matter irrefutably proven then" but let me point out that Dark Matter, while usually in modern context referring to the exotic stuff, still just means anything we can't see yet, and I'd definitely say the consensus is that most matter is dark, what the hell that dark matter is composed of is still heavily debated, but the more mundane alternatives have ever-increasing evidence against them as the lead candidate. I'm not sure how versed you on that evidence, we can discuss it but you'd kinda have to be specific on what your suggesting. I take it though that you're already familiar with the major bits of evidence like the Bullet and Trainwreck clusters, is there anything in particular about those you dispute?
I agree that most matter meets the broad definition of dark matter; in a sense, that's my point: If we're simply talking about non-emitting non-relective normal matter, matter we can see is probably more rare than normal matter we can't, which is to say, neither of them is very exotic at all. Ultimately that was my real point in commenting initially: "Dark matter" is a phrase whose meaning seems to vary with whom you ask, and the evidence for the exotic variety is still inconclusive, so I don't want to count my chickens before they're hatched. I'm probably a little biased in favor of dark matter being a particular type of normal matter because I perceive a bias the other way.