A Billion Tiny Pendulums Could Detect the Universe’s Missing Mass
upstart writes in with an IRC submission:
A Billion Tiny Pendulums Could Detect the Universe's Missing Mass:
Researchers at the National Institute of Standards and Technology (NIST) and their colleagues have proposed a novel method for finding dark matter, the cosmos's mystery material that has eluded detection for decades. Dark matter makes up about 27% of the universe; ordinary matter, such as the stuff that builds stars and planets, accounts for just 5% of the cosmos. (A mysterious entity called dark energy, accounts for the other 68%.)
According to cosmologists, all the visible material in the universe is merely floating in a vast sea of dark matter - particles that are invisible but nonetheless have mass and exert a gravitational force. Dark matter's gravity would provide the missing glue that keeps galaxies from falling apart and account for how matter clumped together to form the universe's rich galactic tapestry.
The proposed experiment, in which a billion millimeter-sized pendulums would act as dark matter sensors, would be the first to hunt for dark matter solely through its gravitational interaction with visible matter. The experiment would be one of the few to search for dark matter particles with a mass as great as that of a grain of salt, a scale rarely explored and never studied by sensors capable of recording tiny gravitational forces.
[...] "Our proposal relies purely on the gravitational coupling, the only coupling we know for sure that exists between dark matter and ordinary luminous matter," said study co-author Daniel Carney, a theoretical physicist jointly affiliated with NIST, the Joint Quantum Institute (JQI) and the Joint Center for Quantum Information and Computer Science (QuICS) at the University of Maryland in College Park, and the Fermi National Accelerator Laboratory.
[...] Because the only unknown in the experiment is the mass of the dark matter particle, not how it couples to ordinary matter, "if someone builds the experiment we suggest, they either find dark matter or rule out all dark matter candidates over a wide range of possible masses," said Carney. The experiment would be sensitive to particles ranging from about 1/5,000 of a milligram to a few milligrams. That mass scale is particularly interesting because it covers the so-called Planck mass, a quantity of mass determined solely by three fundamental constants of nature and equivalent to about 1/5,000 of a gram.
Journal Reference:
Daniel Carney, Sohitri Ghosh, Gordan Krnjaic, et al. Proposal for gravitational direct detection of dark matter [open], Physical Review D (DOI: 10.1103/PhysRevD.102.072003)
Read more of this story at SoylentNews.