Historical research guide · 0482 · 1989

Anomalous weight reduction on a gyroscope’s right rotations around the vertical axis on the Earth

Hideo Hayasaka · Sakae Takeuchi

In one minute

Hideo Hayasaka and Sakae Takeuchi of Tohoku University put spinning gyroscopes on a balance and weighed them. Three of them, with rotors of 140, 175 and 176 grams, spun between 3,000 and 13,000 revolutions per minute, weighed while spinning about the vertical axis. What they report is not a small effect that could go either way; it is a one-sided one. Spin the rotor clockwise seen from above, so that its spin vector points down, and the reading falls by a few milligrams, and the fall grows in step with the rotation rate. Spin it the other way and the reading does not move at all. That asymmetry is the whole result, and it is what makes the Letter interesting, because a mundane error — buoyancy, vibration, magnetism, friction — has no reason to care which way a rotor turns. The paper appeared in Physical Review Letters in December 1989 and set off a decade of weighings.

Connection

Chapter 11 is about whether spinning matter can move the gravitational needle, and this is the measurement that put that question into a first-rank journal. Chapter 8 needs it directly, because the Navy’s inertial-mass-reduction patent builds its mathematics of mass reduction on this Letter’s formula, and chapter 1 gets one of the cleanest teaching cases the site has of how a replication ledger actually reads.

From the source

The weight change of each of three spinning mechanical gyroscopes, with rotor masses of 140, 175 and 176 grams, was measured in inertial rotations, and the authors report the measurement as free of systematic errors.Author abstract; Physical Review Letters 63, 2701 (1989)
The weight changes on rotations around the vertical axis are completely asymmetrical. Right rotations — the spin vector pointing downwards — cause a weight decrease of the order of milligrams, proportional to the frequency of rotation, over the range 3,000 to 13,000 revolutions per minute.Author abstract, principal result
Left rotations do not cause any change in weight. The direction dependence, rather than the size of the shift, is the paper’s load-bearing observation.Author abstract, closing sentence
The authors reduce the effect to a single expression: the weight reduction equals minus 2 times ten to the power minus ten, multiplied by the rotor mass in kilograms, the equivalent gyro-radius in metres and the angular frequency in radians per second.Quoted as Equation 5 of the Navy craft patent held at /library/stm-4678f2e210
Three independent weighings published within fourteen months looked for the same effect and reported none: Faller, Hollander, Nelson and McHugh in Physical Review Letters 64, 825; Nitschke and Wilmarth in Physical Review Letters 64, 2115; and Quinn and Picard in Nature 343, 732, who found no dependence on either speed or sense of rotation. A free-fall test by Luo, Nie, Zhang and Zhou in Physical Review D 65, 042005 in 2002 also returned a null.Crossref records for the four papers, verified for this sheet
The open question is whether those weighings tested the same thing. Pais argues in the Navy patent that none of them fully duplicated the original procedure and setup, singling out the high-vacuum chamber the Hayasaka test section was mounted inside; he also reads the non-zero numerical intercept in the Hayasaka expression, which has units of one per second, as being of the same order as the Fokker-Planck electron-proton thermal equilibration rate for a local vacuum hydrogen number density of about 40 atoms per cubic metre. A weighing that reproduces the original apparatus, vacuum chamber included, at both senses of rotation, is what would settle it.Pais, Craft Using an Inertial Mass Reduction Device, /library/stm-4678f2e210, discussion of the Hayasaka expression and Equations 5 and 6

The way in

https://doi.org/10.1103/PhysRevLett.63.2701

Historical source-access record. This guide links to the original; it does not reproduce the paper text.

WHAT THIS IS. A Letter in Physical Review Letters, volume 63, issue 25, pages 2701 to 2704, 18 December 1989, from Tohoku University. LICENCE AND TEXT. Crossref carries the APS default licence, which is not a licence to republish; OpenAlex and Unpaywall both report the article closed with no repository copy; the APS harvest endpoint answers ‘not authorized’ for this DOI, and no preprint or repository copy was found. No text of the Letter is reproduced here. WHAT WAS READ IN ITS PLACE. Two things. First, the authors’ own abstract, public in the OpenAlex record for the article, which is the source of the rotor masses, the speed range, the direction dependence and the size of the effect. Second, this library’s own copy of the United States Navy patent application ‘Craft Using an Inertial Mass Reduction Device’, at /library/stm-4678f2e210, in which Salvatore Cezar Pais quotes the Hayasaka expression for the weight reduction in full and reads a physical meaning into its non-zero intercept; that text was read here and is the source of the formula and of the reading attributed to Pais. THE FOLLOW-UP RECORD, verified through Crossref for this sheet. Faller, Hollander, Nelson and McHugh, Physical Review Letters 64, 825 to 826, 19 February 1990. Nitschke and Wilmarth, Physical Review Letters 64, 2115 to 2116, 30 April 1990. Quinn and Picard, Nature 343, 732 to 735, February 1990. Luo, Nie, Zhang and Zhou, Physical Review D 65, 042005, 25 January 2002. The skeleton carried no creators; the two authors are added from the Crossref record. The Letter has been cited 60 times.

How to cite it

Hideo Hayasaka, Sakae Takeuchi (1989) Anomalous weight reduction on a gyroscope’s right rotations around the vertical axis on the Earth doi:10.1103/PhysRevLett.63.2701

Where it sits in the curriculum

Gravity control and superconductors