Comments on: It Is Dark. You Are Likely To Be Eaten By A WIMP.

By: Hentzau

Hentzau — Mon, 15 Apr 2013 14:07:17 +0000

The Bullet Cluster observations put a very large hole in MOND but they’re still trying to keep it going by adding in hot neutrinos to explain it away. I don’t pretend to understand the fine details of how or why this shores the theory up, but to me it looks like the same kind of theoretical gymnastics that’s kept string theory going for so long.

By: Gap Gen

Gap Gen — Mon, 15 Apr 2013 13:45:32 +0000

Is there any evidence that MOND solves anything apart from the galaxy rotation problem? I don’t see how it’d explain lensing from the Bullet Cluster or the shape of the CMB, but I could be wrong.

By: Hentzau

Hentzau — Mon, 15 Apr 2013 10:52:11 +0000

Don’t give me an excuse to write about Kepler’s laws. Don’t think I won’t sink that low.

By: Hentzau

Hentzau — Mon, 15 Apr 2013 10:46:35 +0000

Well, it’s more a case of writing new laws of physics vs rewriting old ones. There’s room to bolt WIMPs onto our current physical models without upsetting things too much; saying they’d have to rewrite the Standard Model was a bit of a slip on my part when the Standard Model actually functions kind of like the periodic table, which makes a lot of predictions about elements that weren’t known to exist at the time but which has also been expanded and refined as our scientific understanding of the elements has grown.

MOND on the other hand is tinkering with already existing laws to try to explain away discrepancies between prediction and observation, which most physicists tend to shy away from because it’s exactly what people tried to do to resolve relatavistic phenomena with classical physics before we knew what general relativity was.

(Apologies for the slow reply, I’ve been busy.)

By: Gap Gen

Gap Gen — Thu, 11 Apr 2013 12:09:01 +0000

Yeah, I’d avoid having gas giants move through your cranium at any velocity.

By: jiiiiim

jiiiiim — Thu, 11 Apr 2013 09:48:06 +0000

Well this was entirely made up of stuff I didn’t know (In my head Neptune was going super-fast but over a gigantic distance which explained the longer time). Particle physics, eh.

By: Gap Gen

Gap Gen — Wed, 10 Apr 2013 22:21:05 +0000

Oh, no, stellar evolution follows ego, not parentage. You start with a collection of gas caused by liking the smell of your own farts too much. When enough gas collects it forms a protostar, leading to the sun shining out of your arse. For the largest egos, a black hole will indeed form, causing you to disappear up your own arse.

By: Darren

Darren — Wed, 10 Apr 2013 22:03:09 +0000

EDIT: I should be clear, I mean MOND v. other approaches. They both sound very re-writey to me.

By: Darren

Darren — Wed, 10 Apr 2013 21:53:58 +0000

Could you elaborate on the difference between “rewriting the existing rules of physics” and “identifying an almost completely unknown particle type not explained in the current model but which must have an absolutely massive impact on the functioning of the universe?”

It sounds a little like hair-splitting.

By: Aleksei Volchok

Aleksei Volchok — Wed, 10 Apr 2013 19:50:59 +0000

I’m glad I haven’t mentioned black holes in my question.