Comments on: What is dark matter?

By: Marion Delgado

Marion Delgado — Mon, 08 Aug 2011 18:22:31 +0000

Depends on the explanatory goal. When friends ask I say it’s matter for which there is evidence via gravitational effects including lensing, but doesn’t give off or reflect radiation.

It’s really up to your criterion for explain 🙂

By: bks

bks — Sat, 06 Aug 2011 04:45:49 +0000

Jason, I’m not accusing anyone of anything. *You* invoked/invited McCarthy who is, or plays in this blog, an anti-Materialist. Dark Matter is fodder for anti-Materialism. No big deal, and I do not have a dog in that fight (the philosophical implications of Physicalism/Materialism are not my strong suit.) Apologies if you thought I was aiming at you. I was just reacting to your comment. It was intended to be humor, but I know that doesn’t always work on the net.

–bks

By: Jason Thibeault

Jason Thibeault — Sat, 06 Aug 2011 04:31:34 +0000

Who’s a strong materialist, bks? Could you maybe point to one, and the words they said that make you think so?

By: bks

bks — Sat, 06 Aug 2011 01:40:43 +0000

Timberwoof, physicists needed Special Relativity (1905) to displace Lorentz Ether theory (189?) which worked around Michelson-Morley.

–bks

p.s. Jason, be careful what you wish for; Dark Matter theory can be viewed as a rejection of strong Materialism.

By: Timberwoof

Timberwoof — Sat, 06 Aug 2011 01:03:01 +0000

Inferred by observation? Inferred or observed? What observations? Didn’t Michelson and Morley falsify the ether in 1887?

By: Bert Chadick

Bert Chadick — Fri, 05 Aug 2011 18:11:50 +0000

Dark matter is the aether of the 21st century. Remember that Aether was inferred by observation before 1905. After, not so much.

By: Jason Thibeault

Jason Thibeault — Fri, 05 Aug 2011 04:43:35 +0000

Funny that Anthony McCarthy hasn’t shown up on THIS thread to accuse all of us of being ideologues and mythmakers. We know less about dark matter than we do about abiogenesis.

By: Timberwoof

Timberwoof — Fri, 05 Aug 2011 02:50:21 +0000

Right. Dark matter does not interact with electromagnetic radiation electromagnetically. It does interact gravitationally. And that’s all it does. So while physicists don’t know what it is, they are piecing together limitations on what it can be based on how it behaves.

I suppose it’s fair to say we’re at about the same stage of understanding dark matter as physicists were before the discovery of the neutron. It was postulated to exist, there was some disagreement about what it did, and no one had observed one.

By: Curt

Curt — Thu, 04 Aug 2011 21:47:07 +0000

OK, this explains how we know there is dark matter, but it doesn’t actually answer the question of what dark matter actually is. I’ve got an astronomy buff friend who thinks dark matter is just interplanetary dark bodies and dust which doesn’t glow enough to be accounted for. That never seemed to make sense to me since if the iceberg analogy is right, then it seems to me that most of the sky would be obscured by the stuff. It’s not just that we don’t see dark matter, it’s that we can see other things in spite of it, right? Just wondering in case I ever get into a discussion with him about it again.

By: lynn fellman

lynn fellman — Thu, 04 Aug 2011 15:42:42 +0000

At the very end is a vnice, very quick image / metaphor. An iceberg above the surface that only hints on a much larger story below the surface. A way for the visible to hint at the invisible. Love it!