Gravitational Strength Forces at Short Distances

Research supported by the National Science Foundation


Newton’s 1665 theory of gravity explained why an apple is attracted to the center of the Earth, and why the Earth is attracted to the Sun. It wasn’t until 1798 that Henry Cavendish showed that two objects separated by a meter or so will also be drawn together according to Newton’s universal inverse square law. In modern times, precision tests of the gravitational inverse-square law have covered inter-mass separations from centimeters out to about one light-year, but until very recently we had almost no information about gravity at shorter distances.

Our experiment uses a tungsten torsional oscillator (red, above) to investigate gravity and gravitational strength forces at distances as small as 0.1 millimeter. The source of gravitational field is a tungsten vibrating reed (blue, above). The source and detector are separated by a stiff conducting shield to supress background forces due to electrostatics and residual gas in the vacuum chamber.

More Information

Preprint of our 1998 Nuclear Physics B review of this subject

Preprint of a paper for the MG-9 proceedings

Slides from a talk by Josh Long at Snowmass 2001

News article on this topic by Riley Newman

Related research projects at U. Washington and Stanford

See John Price's vita for a complete list of our publications

Current Participants

Josh Long, Postdoc

Mike Varney, Graduate Student

Elizabeth Watt, Undergraduate

John Price, Professor

Past Participants

Eric Gulbis, Graduate Student

Hilton Chan, Undergraduate

Allison Churnside, Undergraduate

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