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Allais effect

 
Wikipedia: Allais effect
Allais's paraconical pendulum
Photo taken during the French 1999 eclipse

The Allais effect is a claimed anomalous precession of the plane of oscillation of a pendulum during a solar eclipse. It has been speculated to be unexplained by standard physical models of gravitation, but recent mainstream physics publications tend rather to posit conventional explanations for the reported observations.

The effect was first reported in 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 a 1959 solar eclipse.

Prof. Allais’s explanation for this and other anomalies 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.

Exotic explanations for Allais and related effects have not gained significant traction amongst mainstream scientists.

Subsequent observations

A recently published observation of 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. In response to criticisms, the same authors later (2002 and 2003) published papers maintaining that their observations could not be explained by conventional phenomena such as temperature and pressure change caused by the eclipse, and that, although tilting of the ground due to temperature changes could, in the extreme, have been responsible, that hypothesis was unlikely. 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.

Another anomalous effect during a solar eclipse, an increase in the period of a torsion pendulum, was reported by Saxl and Allen in 1970, but subsequent attempts to replicate this experiment (under different eclipse geometries and with much smaller pendulum bobs) failed to observe any effect (Kuusela, 1991; Jun, 1991). Jeverdan in Romania claimed to have observed anomalous pendulum behavior during a solar eclipse in 1961 (Jeverdan, 1981) – decrease of the period by about 1 part in 2000 – the so-called ‘Jeverdan effect’, but his report was not published in a mainstream English-language scientific journal.

A recent 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 for which there is no observational evidence), but admits that ‘the gravitation anomaly discussed here is about a factor of 100,000 too small to explain the Allais excess pendulum precession… during eclipses”.

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.

Eight gravimeters and two pendulums were deployed across six monitoring sites in China for the solar eclipse of July 22, 2009. It is hoped that this effort will resolve the uncertainties surrounding this problem.[1]

References and external links

Footnotes

  1. ^ "July eclipse is best chance to look for gravity anomaly", New Scientist, 2009-07-19 http://www.newscientist.com/article/dn17481-july-eclipse-is-best-chance-to-look-for-gravity-anomaly.html

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