Volume 110, Number 1, April 2015
|Number of page(s)||5|
|Published online||25 May 2015|
Measurements of Newton's gravitational constant and the length of day
1 Jet Propulsion Laboratory, California Institute of Technology - Pasadena, CA 91109, USA
2 Department of Earth, Planetary and Space Sciences, University of California, Los Angeles Los Angeles, CA 90095, USA
3 Department of Physics and Astronomy, University of California Irvine - Irvine, CA 92697, USA
4 Private researcher - Los Angeles, CA 90046, USA
Received: 11 March 2015
Accepted: 27 March 2015
About a dozen measurements of Newton's gravitational constant, G, since 1962 have yielded values that differ by far more than their reported random plus systematic errors. We find that these values for G are oscillatory in nature, with a period of , an amplitude of , and mean-value crossings in 1994 and 1997. However, we do not suggest that G is actually varying by this much, this quickly, but instead that something in the measurement process varies. Of other recently reported results, to the best of our knowledge, the only measurement with the same period and phase is the Length of Day (LOD —defined as a frequency measurement such that a positive increase in LOD values means slower Earth rotation rates and therefore longer days). The aforementioned period is also about half of a solar activity cycle, but the correlation is far less convincing. The 5.9 year periodic signal in LOD has previously been interpreted as due to fluid core motions and inner-core coupling. We report the G/LOD correlation, whose statistical significance is 0.99764 assuming no difference in phase, without claiming to have any satisfactory explanation for it. Least unlikely, perhaps, are currents in the Earth's fluid core that change both its moment of inertia (affecting LOD) and the circumstances in which the Earth-based experiments measure G. In this case, there might be correlations with terrestrial-magnetic-field measurements.
PACS: 04.80.-y – Experimental studies of gravity / 06.30.Gv – Velocity, acceleration, and rotation / 96.60.Q- – Solar activity
© EPLA, 2015
Current usage metrics show cumulative count of Article Views (full-text article views including HTML views, PDF and ePub downloads, according to the available data) and Abstracts Views on Vision4Press platform.
Data correspond to usage on the plateform after 2015. The current usage metrics is available 48-96 hours after online publication and is updated daily on week days.
Initial download of the metrics may take a while.