An Undergraduate Test of Gravitational Time Dilation

ORAL

Abstract

Students at Colorado College and cadets at the US Air Force Academy have conducted an experimental test of gravitational time dilation. This relativistic effect, highlighted in the movie \textit{Interstellar}, causes clocks to tick more slowly near massive objects. A terrestrial measurement of gravitational time dilation was made by comparing signals generated by a GPS frequency standard, which is based on sea-level time, to a cesium-beam frequency standard located at several different elevations across Colorado. The effect is small but observable; for the highest elevation studied (4302 m on the summit of Pikes Peak), a local clock ticks only 41 ns/day faster than a clock at sea level. Our results are consistent with the predictions of general relativity to within the experimental uncertainty. We briefly discuss implications of gravitational time dilation for GPS operations, since the GPS would be useless if time dilation effects are not compensated. This work was supported by grants from the Mellon Foundation fostering civilian/military collaboration.

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Authors

  • Brian Patterson

    United States Air Force Academy

  • M. Alina Gearba

    United States Air Force Academy

  • Jerry S. Sell

    United States Air Force Academy

  • Mario Serna

    United States Air Force Academy

  • M. Shane Burns

    Colorado College

  • Colin Roberts

    High Precision Devices, Boulder, CO, Raytheon, Tucson, AZ, Seagate Technology, Minneapolis, MN, Ball Aerospace (retired), Bloomfield, CO, New Mexico State University, Brigham Young University, Colorado State University, Heinrich-Heine-Universitat Dusseldorf, National Security Technologies, Universidad de Buenos Aires, Colorado State Univ, Colorado College, Utah State University, Advisor, Material Physics Group, Utah State University, Box Elder Innovations, LLC, JILA and Department of Physics, CU Boulder, JILA and Department of Mathematics, CU Boulder, Colorado State University, Fort Collins, Colorado 80523, USA, JILA, NIST and the University of Colorado, Boulder, NIST, University of Colorado / NIST, University of Colorado/JILA, Colorado Sch of Mines, Colorado School of Mines, Southwestern Indian Polytechnic Institute, UC-Berkeley, Colorado State University, Fort Collins, CO, Wroclaw University of Science and Technology, Wroclaw, Poland, JILA, University of Colorado and NIST, Harvard University and Harvard-MIT Center for Ultracold Atoms, Univ of Colorado - Boulder, USAFA, Univ of Denver, Boyce Research Initiatives and Educational Foundation, Brilliant Sky Observatory, San Diego Mesa College, Utah Valley University, University of Colorado Boulder, Brigham Young Univ - Provo, Oak Ridge National Laboratory, University of Sherbrooke, NIST Boulder, Universidad Complutense de Madrid, Electrical and Computer Engineering Department, Colorado State University, Fort Collins, Co 80525, Lawrence Livermore National Lab. (United States), Physics Department, Colorado State University, Fort Collins, Co 80525, JILA, Department of Physics, University of Colorado Boulder, Los Alamos National Laboratory, University of Alabama, University of Wyoming, University of Guelph, University of Guelph, Canadian Light source

  • Jeffrey Steele

    Colorado College