Allais effect

Allais's paraconical pendulum

Photo taken during the French 1999 eclipse

The Allais effect refers to the anomalous behavior of pendulums or gravimeters, which is sometimes observed during a solar eclipse. The effect was first reported as an anomalous precession of the plane of oscillation of a pendulum for the solar eclipse of June 30, 1954 by Maurice Allais, a French polymath who went on to win the Nobel Prize in Economics. He reported another observation of the effect during the solar eclipse of October 2, 1959.

Experimental observations

Various experiments have been performed in order to detect anomalous behavior during solar eclipses. Some observations gave positive results and some failed to detect any noticeable effect. The table below gives an overview of the different experiments.

Experimenter	Date	Place	Device	Result
M. Allais	June 30, 1954	Saint-Germain-en-Laye, France	Paraconical pendulum	"The plane of oscillation of the paraconical pendulum approximately shifted 15 centesimal degr. during the eclipse."
M. Allais	October 2, 1959	Saint-Germain-en-Laye, France	Paraconical pendulum	"An analogous perturbation of amplitude approximately 10 grads has been observed"
G. T. Jeverdan et al.	February 15, 1961	Iasi, Romania	Foucault pendulum	The oscillation period of the pendulum decreased by about 1 part in 2000 – the so-called ‘Jeverdan effect’, but his report was not published in a mainstream English-language scientific journal.
L. Slichter et al.	February 15, 1961	Florence, Italy	Gravimeter	"Gravity observations during the solar eclipse of February 15, 1961, failed to detect an associated gravitational signal"
E. J. Saxl and M. Allen	March 7, 1970	Harvard, Massachusetts	Torsion pendulum	Increase in the period of a torsion pendulum during the solar eclipse: "Quantitative observations made with a precise torsion pendulum show ... that the times required to traverse a fixed fraction of its total angular path vary markedly during the hours before the eclipse and during its first half, i.e., up to its midpoint."
T. Kuusela	July 22, 1990	Turku, Finland	Torsion pendulum	"Contrary to previous experiments, no increase in the period was observed".

A published observation of what was initially claimed to be a possibly related anomalous gravitational effect (claimed variation of terrestrial gravitation as measured by a sensitive gravimeter) was by Wang et al. in 2000, for an experiment carried out in 1997 in a remote region of China during a total solar eclipse. Further observations which the same team performed in 2001 and 2002 during solar eclipses in Zambia and Australia appear to have yielded much weaker evidence of similar anomalies. However, the same authors later (2002 and 2003) published papers explaining that their observations could be explained by conventional phenomena such as temperature and pressure change caused by the eclipse. In their 2002 paper, they posited a more conventional explanation based on temperature changes causing ground tilting, but they suggested that this explanation was unlikely. In their 2003 paper (Flandern and Yang, 2003), on the other hand, the authors argued that atmospheric motion induced by temperature changes was both plausible and sufficient to explain the observed anomaly.

A published article on the topic in a mainstream scientific journal (Flandern, 2003) concludes that there have been "no unambiguous detections [of an Allais effect] within the past 30 years when consciousness of the importance of [experimental] controls was more widespread." This paper also suggests a mechanism that might cause slight gravitational variations during an eclipse (high speed high-altitude winds). They point out that "the gravitation anomaly discussed here is about a factor of 100,000 too small to explain the Allais excess pendulum precession… during eclipses" and from this conclude that the original Allais anomaly was merely due to poor controls.

A possible but yet controversial explanation is the so-called van Flandern–Yang hypothesis by van Flandern and Yang's article, which conjecture the effect is due to the gravitational effect of an increased density spot in the upper atmosphere created by cooling during the solar eclipse.

A self-published review article by Chris Duif, which surveys the field of gravitational anomalies in general, concludes that the question remains open, and that such investigations should be pursued, in view of their relatively inexpensive nature and the enormous implications if genuine anomalies are actually confirmed – but the article has not undergone any peer review.

During the solar eclipse of January 26, 2009, a correlation was found between anomalous behavior of a pendulum and torsion balances, located at two different points outside the shadow zone.

Eight gravimeters and two pendulums were deployed across six monitoring sites in China for the solar eclipse of July 22, 2009. Although one of the scientists involved claimed in an interview to have observed an Allais effect, the result has not been published in any mainstream peer-reviewed scientific journal.

An automated Foucault pendulum was used by H.R. Salva and found no evidence for a precession change of the pendulum's oscillation plane (<0.3 degree / hour) during the Solar eclipse of July 11, 2010.

Explanations

Maurice Allais states that the eclipse effect is related to a gravitational anomaly, that is inexplicable in the framework of the currently admitted theory of gravitation, without giving any explanation of his own. Allais’s explanation for another anomaly (the lunisolar periodicity in variations of the azimuth of a pendulum) is that space evinces certain anisotropic characteristics, which he ascribes to motion through an aether which is partially entrained by planetary bodies. He has presented this hypothesis in his 1997 French book L’Anisotropie de l’espace. This explanation has not gained significant traction amongst mainstream scientists.

After analysis of Foucault pendulum data during the solar eclipse of July 11, 1991, L. Savrov suggested that the "pendulum responded to the remanent shock wave at the maximum of the total eclipse phase".

External links

• Maurice Allais, Ten Notes published in the Proceedings of the French Academy of Sciences (Comptes Rendus des Seances de l'Academie des Sciences), dated 4/11/57, 13/11/57, 18/11/57, 13/5/57, 4/12/57, 25/11/57, 3/11/58, 22/12/58, 9/2/59, and 19/1/59, available in French at www.allais.info/alltrans/allaisnot.htm, some also in English translation.
• Maurice Allais, "The Allais Effect and my Experiments with the Paraconical Pendulum 1954–1960" (Report for NASA, 1999)
• T. van Flandern and X. S. Yang, "Allais gravity and pendulum effects during solar eclipses explained," Phys. Rev. D 67, 022002 (2003).
• Qian-shen Wang, Xin-she Yang, Chuan-zhen Wu, Hong-gang Guo, Hong-chen Liu, and Chang-chai Hua, "Precise measurement of gravity variations during a total solar eclipse," Phys. Rev. D 62, 041101(R) (2000).
• X. S. Yang and Q. S. Wang, "Gravity anomaly during the Mohe total solar eclipse and new constraint on gravitational shielding parameter," Astrophysics and Space Science 282 (1), 245–253 (2002).
• Luo Jun, Li Jianguo, Zhang Xuerong, V. Liakhovets, M. Lomonosov, A. Ragyn, "Observation of 1990 solar eclipse by a torsion pendulum," Phys Rev. D. 44, 2611–2613 (1991).
• T. Kuusela, J. Jäykkä, J. Kiukas, T. Multamäki, M. Ropo, and I. Vilja, "Gravitation experiments during the total solar eclipse," Phys. Rev. D. 74, 122004 (2006).
• Chris P. Duif, "A review of conventional explanations of anomalous observations during solar eclipses," arXiv gr-qc/0408023 v3 (8 Oct 2004). (Unpublished preprint claiming that Allais observations do not satisfy conventional explanations.)
• Dave Dooling, "French Nobel Laureate turns back clock", Science@NASA (Oct. 12, 1999). A 1999 NASA attempt to observe an Allais effect; no results are reported. No results were ever published.
• Thomas J. Goodey, "Professor Maurice Allais — a genius before his time — as are they all" (Web site claiming to be the internet base of researchers studying and publicizing the Allais effect; includes copies/translations of several of the above papers.)
• Göde Wissenschafts Stiftung "Experimental measuring results with the paraconical pendulum
• Ed Oberg "www.iasoberg.com" This site has been established by Ed Oberg to facilitate and promote research into the Allais Effect and to distribute the resulting findings. The launch of this site (23 November 2007) coincided with the launch of a hypothetical field model developed by Ed Oberg.