Maurice Allais, the recently dead "Nobel" laureate in economics, experimented with a paraconical pendulum during the 1950s. He discovered the Allais effect, which is a variation in the behavior of a pendulum during an eclipse. The plane of the pendulum rotated approximately ten degrees during the eclipse and then returned to the previously pattern. A number of scientists have tried to replicate this and similar effects with various experimental equipment during various eclipses. Some succeeded in replication and some failed. Allais’ explanation, apparently, was to revive the 19th century concept of the aether and argue that space is anisotropic.
Pioneers 10 and 11 were launched in 1972 and 1973, respectively. NASA was still in communication with them after they had passed beyond the orbit of Pluto and were more than 20 Astronomical Units away from the sun. (An AU is the average distance from the Earth to the sun.) Pioneers 10 and 11 have an anomalous acceleration towards the sun of an order of magnitude of 10-7 centimeters per square seconds. In other words, as they move away from the sun, they are very slowly slowing down more than can be accounted for under the current (relativistic) understanding of gravity. Pioneers 10 and 11 are moving away from the sun at a rate of approximately 12 kilometers per second. (It dawned on me while writing the above that I am no longer sure how many planets are in our solar system.)
- Maurice Allais (1986). "The Concepts of Surplus and Loss and the Reformulation of the Theories of Stable General Equilibrium and Maximum Efficiency", in Foundations of Economics (edited by Mauro Baranzini and Roberto Scazzieri), Basil Blackwell.
- John D. Anderson et al. (1998) "Indication, from Pioneer 10/11, Galileo, and Ulysses Data, of an Apparent Anomalous, Weak, Long-Range Acceleration", arXiv:gr-qc/9808081v2 (1 October)
- John D. Anderson et al. (2005) "Study of the Anomalous Acceleration of Pioneer 10 and 11", arXiv:gr-qc/0104064v5 (10 March)
- Gibor Basri and Michael E. Brown (2006) "Planetesimals to Brown Dwarfs: What is a Planet?", Ann. Rev. Earth Planet. Sci., V. 34: pp. 193-216
- M. E. Brown, C. A. Trujillo, and D. L. Rabinowitz (2005) "Discovery of a Planetary-Sized Object in the Scattered Kuiper Belt", The Astrophysical Journal, 635: L97-L100, (10 December)
- Chris P. Duif (2004) "A Review of Conventional Explanations of Anomalous Observations during Solar Eclipses", arXiv:gr-qc/0408023 v5 (31 December)