wrote:

In sci.astro Uncle Al wrote:

By hypothesis and definition dark matter does not interact except by
gravitation.

Not true. By hypothesis, dark matter interacts weakly, but there is
certainly no requirement of no nongravitational interaction. In fact,
popular candidates (lightest supersymmetric particle, axions) certainly
do have nongravitational interactions. In fact, a major experimental
effort is going into searches for dark matter through such interactions.

Steve Carlip

CERN's axion telescope has proven to be cold manure. Collar's dark
matter detector Halon and perfluorocarbon bubble chambers are
brilliant but not implemented at scale. (If he wants to make a grant
funding splash he'll need a totally ridiculous, er, advanced working
fluid boiling around 0 C, like heptakis(trifluoromethyl)iodine. No
static molecular structure!) Ultracryogenic dark matter collision
phonon detectors are in place and working.

NO DETECTIONS. Gravity Probe B (such as it was) showed no anomaly.
Lunar laser ranging shows ZERO Nordtvedt effect.

Uncle Al calls "bull****" on undetected matter in space in sufficient
quantities to detectably alter local orbits, by collision
cross-section or by naked gravitation. If somebody comes up with a
reproducible lab signal (not the Italian stuff), Uncle Al will
apologize.

--
Uncle Al
http://www.mazepath.com/uncleal/
(Toxic URL! Unsafe for children and most mammals)
http://www.mazepath.com/uncleal/lajos.htm#a2