Comments on: Guest Post: Neal Weiner on The Era of Dark Matter Direct Detection

By: Flash Starwalker

Flash Starwalker — Wed, 02 Mar 2011 00:32:15 +0000

This is very exciting. If they really find WIMPs it will falsify Jack Sarfatti’s theory that dark matter is really / < 0 vacuum fluctuation energy with positive pressure with w = -1. Since positive pressure outweighs negative energy density by a factor of 3 in isotropic situations the net result is attractive gravity in GR where the effective source is (energy density)(1 + 3w). The clumping makes this AdS vacuum phase indistinguishable from w = 0 CDM in gravity lensing et-al. Thus Sarfatti compares the search for WIMPS with the Michelson-Morley search for the motion of Earth through the Newtonian aether, i.e. a null result.

By: This “Week” in the Universe: February 1st – February 21st | EntroPop

This “Week” in the Universe: February 1st – February 21st | EntroPop — Thu, 24 Feb 2011 02:11:16 +0000

[...] this month, there was a really excellent guest post at Cosmic Variance about the state of dark matter detection experiments by Neal Weiner (to complete the discussion of [...]

By: OldGrump2U

OldGrump2U — Thu, 17 Feb 2011 21:42:23 +0000

2 simple questions from this simple mind:

Does Dark Energy exist?

Is it possible the zero point energy that some are reporting is actually Dark Energy?

TIA

By: rationalist

rationalist — Thu, 10 Feb 2011 19:08:03 +0000

Sean: You should invite a post from Stacy McGaugh — one of the leading experimentalists in dark matter refutation. he’s a professor at UMD, http://www.astro.umd.edu/~ssm/

By: Dunkle Materie direkt detektieren: Durchbruch (bald)? « Skyweek Zwei Punkt Null

Wed, 09 Feb 2011 00:12:57 +0000

[...] werden wir entweder genau wissen, aus was die Dunkle Materie besteht – oder woraus nicht. Cosmic Variance 3.2. Auch eine PM der JGU Mainz zu deren Beitrag zu XENON 100, Nature zu Ärger um das [...]

By: Eric Habegger

Eric Habegger — Mon, 07 Feb 2011 16:59:49 +0000

OK.

By: Valatan

Valatan — Mon, 07 Feb 2011 14:37:25 +0000

Why is the Milky way flat? Why does it have remnant clusters with a more spherical distribution that appear much older than your average Milky Way star? Why do these clusters seem to have roughly the same distribution as the dark matter?

hint: it all has to do with the interaction between stars and dust.

By: Eric Habegger

Eric Habegger — Mon, 07 Feb 2011 04:41:40 +0000

First question: what do you mean by stuff falls into the middle of galaxies due to friction?

Second question: what are you implying as the force causing friction?

Third question: why would turning the friction off in the case of sterile neutrinos move them to the edge of the galaxy?

You are assuming the normal forces that might somewhat randomize the distribution of regular massive particles do not do that to sterile neutrinos (one could also substitute Wimps here). That implies that the distribution of massive particles in the galaxy would not affect the distribution of
neutrinos. But on the other hand you are also saying that the heavy distribution of those neutrinos ARE affecting the massive particles on the edge of galaxies and keeping them from drifting off. Those are contradictory attributes that you are requiring neutrinos to have.

By: Valatan

Valatan — Mon, 07 Feb 2011 02:40:34 +0000

You’d expect any weakly coupled particle to be heavily distributed at the edge of galaxies–stuff falls into the middle of galaxies due to friction, and if you turn the friction off (which is certainly true of sterile neutrinos–they wouldn’t see ordinary matter), they just stay where they are, unlike luminous matter, which interacts with the ISM.

By: Eric Habegger

Eric Habegger — Sun, 06 Feb 2011 23:14:20 +0000

@Valatan,

A right handed neutrino perhaps isn’t more exotic than an axion. However the apparent heavy distribution of those right handed neutrinos at the edge of galaxies would be.