Gravitational Research Laboratory

Location: Science A - Room 264
Phone: 707-826-4981
Principal Investigator: C.D. Hoyle, 707-826-3235

Primary Research Areas

  • Short-range tests of Newton's 1/r² law and the Weak Equivalence Principle
  • Searches for new fundamental forces
  • Investigation of the mechanism behind Dark Energy
  • Measurement of the Newtonian Gravitational Constant, G


  • Torsion Pendulum tests of gravity with the Eöt-Wash group at the University of Washington. This group’s leaders won the 2021 Breakthrough Prize in Fundamental Physics.
  • Development of a new experiment to measure the gravitational constant with Professor Ricardo Decca at Indiana University-Purdue University of Indianapolis (IUPUI).
  • Development of the LAG experiment to test gravity at short distances in collaboration with Dr. Luciano Di Fiore of the INFN (Italian Institute of Nuclear Physics) and Dr. Rosario De Rosa of the University of Naples Federico II (Italy).


After over 300 years of experimentation, the true nature and implications of gravity are not fully understood. Here at Humboldt, we are creating a laboratory to investigate the subtle properties of this familiar force of nature.

Gravity and quantum mechanics are fundamentally inconsistent in the current frameworks of the Standard Model and General Relativity. String theory promises a possible resolution of this issue at the cost of introducing new spatial dimensions (Arkani-Hamed, et al.). These dimensions will necessarily alter the Newtonian inverse-square law on distance scales similar to that of the size of these extra dimensions.

Gravity Lab in the News

Presentations & Publications

Recently published peer-reviewed articles (*indicates undergraduate authors):

"Optimization of an Active Leveling Scheme for a Short-Range Gravity Experiment,"
Alyssa Johnson*, Claire Rogers*, Noah Dunkley*, Michael Gengo*, and C.D. Hoyle, Journal of Undergraduate Reports in Physics (JURP) 33, 100002 (2023)

"Measurement of gravitational and thermal effects in a liquid-actuated torsion pendulum," A. Allocca, M. Bassan, M. De Laurentis, R. De Rosa, L. Di Fiore, L. D’Onofrio, L. Errico, F. Garufi, A. Grado, C.D. Hoyle, D. Lucchesi, Y. Minenkov, G. Passeggio, G. Pucacco, V. Sequino, O. Tarallo, L. Trozzo, and M. Visco, Rev. Sci. Instrum. 94, 114501 (2023)

"Fifteen Years of Millimeter Accuracy Lunar Laser Ranging with APOLLO: Data Set Characterization," J.B.R. Battat1, E. Adelberger, N.R. Colmenares, M. Farrah, D.P. Gonzales, C.D. Hoyle, R.J. McMillan, T.W. Murphy Jr., S. Sabhlok, and C.W. Stubbs, Publications of the Astronomical Society of the Pacific 135, 1052 (2023)

"A modified Michelson interferometer to measure sub-milliradian changes in angle," C.K. LeDesma*, M.P. Ross*, B.E. Daly*, C.D. Hoyle, and M.M. Mola, AIP Advances 12, 085002 (2022)

Students and faculty who work in the gravity lab have given more than 35 presentations at regional and national meetings, including those of the American Physical Society, National Conference on Undergraduate Research, and the Pacific Coast Gravity Meeting, to name a few. The lab has published peer-reviewed work in undergraduate research journals and we have several publications currently in the pipeline!


The material on this site is based upon work supported by the National Science Foundation grants PHY-1065697, PHY-1306783, PHY-1606988, PHY-1708024, PHY-1908502, and PHY-2207801, as well as the Gordon and Betty Moore Foundation Grant GBMF6210 to the American Physical Society. We are also grateful for financial support provided by the Cal Poly Humboldt College of Natural Resources and Sciences, Sponsored Programs Foundation, and Research Corporation grant CC6839.

Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation.


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Current Students

  • Kevin Chung
  • Taylor Juchau
  • Abby Keltz
  • Alexandra Papesh
  • Evan Rosales
  • Kelsey Sako

Former Students

  • Samantha Anger
  • Brandon Baxley
  • Kolby Bell
  • Garrett Benson
  • Crystal Cardenas
  • Zane Comden
  • Bret Comnes
  • Stephanie Corah
  • Jacob Crummey
  • Berlin Del Aguila Garcia
  • Noah Dunkley
  • Holly Edmundson
  • Liam Furniss
  • River Galaz
  • Michael Gengo
  • Enrique Guerrero
  • Ian Guerrero
  • A. Conrad Harter
  • Jeff Herr
  • Nicholas Hernandez
  • Tanner Hooven
  • Hilde Isachsen
  • Alyssa Johnson
  • Jeremy Johnson
  • Edward Kemper
  • Catherine Ledesma
  • Marika Leitner
  • Luis Lemus
  • Holly Leopardi
  • Gabriela Martinez
  • Jesse Mendez
  • Emily Ord
  • Nathan Rasmussen
  • Matthew Richards
  • Claire Rogers
  • Michael Ross
  • Tony Sanchez
  • Duncan Shaw
  • David Shook
  • Tyler Smart
  • David Smith
  • Jackson Stillman
  • Jahaira Valencia Santoyo
  • Frankie Trombetta
  • Adam Turk
  • Kassandra Weber