Decrypting the Eclipse
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Decrypting the Eclipse
A Solar Eclipse, Global Measurements
and a Mystery
and a Mystery
"During the total eclipses of the sun on June 30,
1954, and October 22, 1959, quite analogous deviations of the
plane of oscillation of the paraconical pendulum were observed..."
- Maurice Allais, 1988 Nobel autobiographical
lecture.
August 6, 1999: The natural phenomenon of a solar
eclipse has historic
ally brought kings to assemble
armies and, in the modern era, brought camera-toting astronomers
to remote locations around the world. On August 11, a solar eclipse
will bring scientists together in an effort to solve a 45-year
mystery.
Right: When the Moon eclipses the Sun, the solar corona
becomes visible. The corona is faint compared to the Sun, so
it can only be seen when the Sun is blocked from view. Jean Bernard
Leon Foucault, with the physicist Armand Fizeau, took the first
clear photograph of the Sun in 1845.
The mystery lies in the question: Does a solar eclipse somehow affect a Foucault pendulum? In 1954, Maurice Allais reported that a Foucault pendulum exhibited peculiar movements at the time of a solar eclipse. If true, his finding raises new questions about the nature of such phenomena.
For the upcoming eclipse, the NASA/Marshall Space Sciences Lab is coordinating an internet and video collaboration between observatories and universities to test the Allais effect. Participants on 4 continents (Central Europe, North America, Middle Asia, and Australasia), are from at least 7 countries (US, Austria, Germany, Italy, Australia, 4 sites in the United Arab Emirates, and England) and 11 cities (Huntsville, AL, Indianapolis, Louisville, Denver, Boulder, Richmond, Vienna, Greifswald, Trento, Abu Dabi, and Sydney).
Educators!
Please visitThursday's Classroom for lesson plans and activities related to the August 11, 1999 total solar eclipse. |
e Earth. A scientific tour de
force, Foucault's demonstration forever attached his name both
to the effect itself (the Foucault effect) and to the universal
joint pendulum that freely swings and rotates at the same time
(the Foucault pendulum).Left: Time-elapsed photo of a Foucault pendulum at the Smithsonian Museum. As the Earth rotates under the pendulum, the bob strikes down red pegs.
A basic Foucault pendulum is simply a weight on a wire. Practically any pocket watch has the potential to act as a pendulum, exhibiting up to a 10 to 15 degree rotation per hour around its hinge point. To an observer in a windowless room, the rotation that accompanies the swing is a kind of optical illusion: the pendulum is not turning, instead the Earth is actually rotating under the pendulum. Foucault's dramatic proof at the World's Fair is considered to be the first non-astronomical proof of the Earth's rotation.
With rotating hinges raised to heights in excess of 90 feet,
Foucault pendulums are now massive display pieces in the lobbies
of more than 60 museums and entrance halls around the wo
rld,
including the United Nations Building in New York and at the
Smithsonian Museum in Washington.
Remarkably, little more than two long-term scientific records for Foucault pendulums have been published. Both experiments were conducted by eventual Nobel Prize winners: Heike Kamerlingh-Onnes, who won the 1913 Nobel prize in Physics for his investigations on the properties of matter at low temperatures (which led to the production of liquid helium), and Maurice Allais, who won the 1988 Nobel prize in Economics for his contributions to the theory of markets and efficient utilization of resources.
An Abrupt Excursion in the Plane: What Allais Published
In a marathon experiment, Maurice Allais released a Foucault
pendulum every 14 minutes - for 30 days an
d nights -without missing a data
point. He recorded the direction of rotation (in degrees) at
his Paris laboratory. This energetic show of human endurance
happened to overlap with the 1954 solar eclipse. During the eclipse,
the pendulum took an unexpected turn, changing its angle of rotation
by 13.5 degrees.
Left: Maurice Allais (1911 - ) won the Nobel Prize
in Economics in 1988. He stated, "All my researches in theoretical
and applied physics which, at first sight, appear to be remote
from my main activity as an economist, have, in reality, enriched
me with valuable experience."
Both before and after the eclipse, the pendulum experienced
normal rotation (Foucault effect of 0.19 degrees/minute). This
13.5-degree excursion in the angular plane persisted throughout
the length of the eclipse, a total of 2.5 hours of observations.
Allais got similar results when he later repeated the experiment
during a solar eclipse in 1959.
Right:
Foucault clock animation - each tick shown is one hour worth
of observed rotation. Depending on geographic position, the rotation
of the Earth on a Foucault clock can be measured as different
rotation rates: infinite period at the equator; approximately
24 hours at the poles; clockwise in the Southern Hemisphere;
counter-clockwise in the Northern Hemisphere. The Allais effect
observed over 2 and an half hours during the shadow of an extended
solar eclipse's onset and departure equals nearly the magnitude
of the Foucault effect itself (or about one tick shown).
Allais' pendulum experiments earned him the 1959 Galabert
Prize of the French Astronautical Society, and in 1959 he was
made a laureate of the United States Gravity Research Foundation.
A handful of scientists have since tested Allais' findings, and
the results have polarized the publication record:
October 1959
YES: Allais' original observations were repeated 3 times in 1954 and 1959 in France. In two locations: "two identical installations at St. Germain and Bougival, in an underground gallery (57 m deep) showing that the previously observed anomalies are still present." Allais, 1959.
Italy, 1965
NO: Given a null report in 1954 in Shetland, Scotland using static gravity meters, and in 1965 in Trieste, Italy.
pendulum
YES: The Allais effect was repeated in 1961 in Romania. "A number of observations were made of the behavior of a Foucault pendulum during the eclipse of the Sun of February 15, 1961. A similar result concerning a shift of the oscillation plane on June 30, 1954 was seen by Prof. Maurice Allais at St. Germain-Laye. These experiments should be repeated during other total eclipses of the sun." G.T. Jeverdan, et al, 1961 (A footnote states that after recording their deviations in the Foucault pendulum, the researchers discovered the Allais observations. In other words, they weren't looking for it.)
pendulum
pendulum
pendulum
MAYBE: The team that conducted the Finland 1990 study
detected an indefinite signal one year later in Mexico City.
"In the y-position of the pendulum there are two distinct
shifts which seem to appear at the beginning and the end of the
eclipse... Our experiment cannot determine whether these shifts
are produced by some eclipse-coordinated phenomena, e.g. some
sort of tidal waves on the shell of the Earth which has altered
the position of the pendulum system."
gravimeter
"The initial interpretation of the record points to three possibilities," says Dr. David Noever of NASA/Marshall, "A systematic error, a local effect, or the unexplored. To eliminate the first two possibilities, we and several other observers will use different kinds of measuring instruments in a distributed global network of observing stations."
Worldwide Effort, August 11, 1999
Testin
g
and then verifying the effects of a solar eclipse is a difficult
enterprise. Because an eclipse has a short duration, it is difficult
to conduct very many tests. Also, eclipse effects usually get
attributed to some local effect like seismic or temperature changes
because the experiments are not conducted in several different
places at once. Therefore, in order to determine whether or not
the effects of any single eclipse are one-time, localized events,
many observing stations are needed to test eclipse peculiarities.
During the next solar eclipse, Noever's team and volunteer scientists
at several museums will simultaneously observe Foucault pendulums.
Noever and other scientists will also use a gravimeter - a super-sensitive
device that reports very small changes in the gravitational force
acting on a mechanical spring.
After the eclipse, Noever's team will compare the results of
all the tests, including observations from areas in Europe that
lie in the path of the eclipse.
Left: Cutaway view of gravimeter, with magnetic, thermal
and pressure shielding. The instrument reports very small changes
in the gravitational force acting on a mechanical spring-mass.
Gravitational changes are expressed as the electrical force (measured
as voltage) required to maintain the spring-mass system at a
predetermined position (the null point). The modified LaCoste-Romberg
gravimeter (Edcon, Inc. Denver, CO) measures relative gravity
until calibrated against a reference. The instrument is routinely
calibrated along the 10-station Rocky Mountain Calibration range
established by NOAA, Edcon and the Colorado School of Mines.
The calibration is validated by comparing the measure of absolute
gravity in Huntsville Alabama with reference values from the
USAF gravity disk.
Data collection begins on August 11. The times of the solar eclipse are 3am-9am in North America, and 9a.m.-3p.m. in Europe and Middle Asia. These times can be adjusted for exact locations, for instance, in Boulder, CO, a data set for recording would be about 2:30a.m., continuing until 8:30a.m. That would cover the approach of the shadow, the actual eclipse, and the retreat of the shadow. The total length of the eclipse from initial contact in the Atlantic to last contact in the Indian Ocean is about 3 ½ hours.
Eclipsing Speculation
If the scientists do observe the Allais effect, the prevailing
question will be "Why does it occur?" So far, explanations
have included the anisotropy of space (the condition of having
different properties in different directions), gravitational
waves, and solar radiation.
| Web Links |
The
Foucault Pendulum -- an excellent tutorial discussion by
Professor B. Nickel, Physics Department, University of Guelph,
Ontario, Canada. This web site also reviews some peculiarities
in pendulum motion detected by experiments at the University
of Guelph. Fred Espenak's Solar Eclipse Home Page - at the NASA/Goddard Space Flight Center. |
But before the cause of the Allais effect can be determined, scientists first need to settle the question about whether a pendulum really does act differently during a solar eclipse. By having a global network of scientists collaborating on a single eclipse, the answer to that question will perhaps finally be resolved.
Results of August 11 eclipse will have to be coordinated with
lunar opposition (2 weeks later) before a first summary of eclipse
data will be available. Realistically, scientists think it will
take at least a decade before all opinions are settled.
In his Nobel Prize autobiographical speech, Allais stated, "My
main idea at the start was that a link could be established between
magnetism and gravitation by observing the movements of a pendulum
consisting of a glass ball oscillating in a magnetic field. Of
all the observations made in 1952 and 1953 I was not able to
draw any definitive conclusion. Through certain experimental
devices, I obtained positive effects, but with other devices
I obtained no effect whatsoever....all these phenomena are quite
inexplicable within the framework of the currently accepted theories."
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Upon learning of the upcoming effort to investigate the pendulum-eclipse mystery, Allais said he was glad and excited that scientists are revisiting his experiments. The German rocket scientist Werner von Braun, one of the original rocket team members at NASA's Marshall Space Flight Center, had encouraged Allais to translate one of his pendulum experiments from French into English. Von Braun, it seems, believed the experiment could explain anomalies in some space object trajectories. When the pendulums start swinging on August 11, the early connection between Allais and NASA/Marshall will have come full circle.
Although much of Europe, Asia and Africa will witness the eclipse, only those who lie directly under the path will see a total eclipse. Other than partial coverage at dawn in the Northeast corridor, North American sites appear in opposition to the ground shadow. But if effects have a gravitational origin, previous studies would indicate any detection may depend more on instrument resolution. To better than one part in 10 billion, no evidence of material shielding of gravity has ever been detected.
To
see detailed maps of the path of totality, click on the regions
specified below:
France, Belgium, Luxemborg and Germany
The path of totality will begin in the Eastern edge of North America, run through Europe and the Middle East, and end in India . credit: Fred Espenak and Sky and Telescope
The Dark Side of the Eclipse - Science, July 2, 1999.
Autobiography of Maurice Allais - Copyright ©1999 The
Nobel Foundation
Mephistos
UCLA - With Pasteur and Darwin, Foucault ranks as one of
the top three scientific influences in 19th century science.
Three
Spacecraft Reveal Unexplained Motions - from Newswise
The Space Environment - Sunlight and Earthshine
The
Speed of Gravity - Tom Van Flandern
Big Bang Acceleration -- Observations of supernova explosions halfway back to the Big Bang give plausible evidence that the expansion of the universe has been accelerating since that epoch, approximately 8 billion years ago and suggest that energy associated with the vacuum itself may be responsible for the acceleration.
The 1990 solar eclipse as seen by a torsion pendulum
A possible explanation for the anomalous acceleration of Pioneer 10
The Apparent Anomalous, Weak, Long-Range
Acceleration of Pioneer 10 and 11
Bottlinger's
and Majorana's absorption of the gravitational force and the
tide-generating forces
The screen effect of the earth in the
TETG - Theory of a screening
experiment of a sample body at the equator, using the earth as
a screen.
A
method for detecting gravitational waves with the aid of torsion
pendulums
Effect of solar rotation on free vibrations of a torsional pendulum
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