Yousuf Khan wrote:

A New Look at Newton's Second Law Could Explain Away the Existence of
Dark Matter | Popular Science
"A team headed by Vitorio De Lorenci of the Federal University of
Itajubá, Brazi devised an experiment that could finally try to directly
test MOND. They discovered that certain points on a well-placed,
precisely-controlled spinning disc can cancel out the acceleration of
the Earth's rotation, its orbit around the sun, and the orbit of the sun
around the galaxy's center.

Canceling out all those interfering accelerations would allow for a
measuring device mounted on the disc's rim to work unimpeded. If
Newton's second law holds as usual, the device should not detect any
unusual force. But if MOND holds true, the device should feel a strange
kick."
http://www.popsci.com/science/articl...er-explanation

Our first observation is that the URL was written by an imbecile.

http://arxiv.org/abs/1002.2766

J.P. Pereira is a reputable physicist who has extensively written
about teleparallel gravitation (in which the effects of a massive body
are not geodesic paths but force equations. If spacetime is not
geometrized, many of the intrinsic difficulties of converting
classical to quantum gravitation do not arise. OTOH, the force
equations are like right hand rules. Left and right shoes can vacuum
free fall differently. There is nothing a theorist fears more than a
bench experiment).

"Since the possible corrections implied by this approach would be
applicable only at very low accelerations (a_o ~ 10^(-10) m/s^2) it
should be improbable to detect the effects of MOND in
terrestrial-based experiments."

The very best vacuum free fall gravimeters with averaged outputs are
good to 10^(-9) relative or about 10^(-8) m/s^2 absolute. An Eotvos
balance in the best isolation, averaged over 90 days, is good to
5x10^(-14) relative or almost 5x10^(-13) m/s^2 *between* its test
masses. It measures nothing as an absolute output.

"In these two spots, of around 0.1 m^3 occurring for only a few
seconds in each equinox date, static particles would experience a
subtle acceleration caused by the MOND regime." [For the 2008
equinox, coordinates theta = 79 degrees 50 minutes and phi = ~56
degees West.]

Something must be rigged for large volume continuous measurement. Can
this be achieved? No.

"what is the size of the ring for which the required small
acceleration regime holds and how long is the ring available for a
measurement?" [orientation, then 5x10^(-3) m/s^2 located at the poles
and 3x10(-2) m/s^2 located at the equator to cancel external Coriolis
and orbital accelerations]

They are diddling 10^(-3) background to measure less than a 10^(-10)
m/s^2 originating anomaly. Not good.

"the small acceleration regime occurs within in a region of length of
the order /_\L 10^(-7) m in the direction of the angular movement of
the ring."

Woof. The time interval is less than a microsecond in an overall area
less than 10^(-8) m^2. Uncle Al already knows the results! "More
studies are needed."

"IT IS NOT THE SCOPE OF THIS PAPER TO DEVELOP THE REQUIRED SETUP FOR
THIS IN DETAIL"

Yeah.

"the experiment must be completed so that uncertainties are acceptable
only up to the 10th decimal digit."

It doesn't even work on paper. An FT-NMR proton or F-19 nuclear
precession experiment could not begin to fit in the most optimistic
estimated created active volume over the maximum alloted timespan.

--
Uncle Al
http://www.mazepath.com/uncleal/
(Toxic URL! Unsafe for children and most mammals)
http://www.mazepath.com/uncleal/qz4.htm