TOTAL ECLIPSE OF REASON? In the physics equivalent of an urban legend, the late astronomer Sir Arthur Eddington is sometimes alleged to have rejected data that didn't fit his preconceptions in a famous test of Einstein's general relativity during the 1919 solar eclipse.
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On May 29, 1919, two British expeditions, positioned on opposite sides of the planet, aimed telescopes at the sun during a total eclipse. Their mission: to test a radical theory of gravity dreamed up by a former patent clerk, who predicted that passing starlight should bend toward the sun. Their results, announced that November, vaulted Albert Einstein into the public consciousness and confirmed one of the most spectacular experimental successes in the history of science.
In recent decades, however, some science historians have argued that astronomer Sir Arthur Eddington, the junior member of the 1919 expedition, believed so strongly in Einstein's theory of general relativity that he discounted data that clashed with it.
In 1919 general relativity was on the cusp of eclipsing Sir Isaac Newton's law of universal gravitation, put forth in 1687. Newton's law cast gravity as a type of bond between objects, all floating within the gridlike arena of space and time. Einstein's insight was that gravity is the grid, which is warped by massive objects such as the sun. As a consequence, light passing the sun should literally fall toward it like a moon rover clipping the edge of a giant crater and falling in.
Eddington, then director of the University of Cambridge Observatory, convinced his senior colleague and England's Astronomer Royal, Sir Frank Dyson, to mount the expedition. The group split into two teams: Dyson's crew from what was then the Royal Observatory in Greenwich headed to the town of Sobral, Brazil, as Eddington and cohorts set up on the western African island of Príncipe. Their task was to independently record the positions of the stars near the moon-blotted sun and compare them with the positions of the same stars at night.
If general relativity was right, the apparent positions of the nearest stars would drift 1.75 arc seconds (a measure of angularity) closer to its rim during the eclipse (a pencil width seen at half a mile). Eddington was hampered by overcast skies on the long-awaited day and photographed only five stars. It was too few for a solid result, but he gave some weight to his final value of 1.61 arc seconds.
Dyson's team had mixed results. One of the group's two telescopes functioned correctly and gave them a value of 1.98 arc seconds. The second instrument yielded a value of 0.93 arc second, which was rather close to the Newtonian prediction of 0.87. The instrument, however, had lost focus during the eclipse, which cast doubt on the accuracy of the photo comparison, so they excluded the measurement from their final result. Based on the remaining evidence, they declared general relativity triumphant.
Over time, experts looked askance at the sweeping conclusion, which both ignored the possibility that some other theory of gravity might have better fit the results and also didn't match general relativity very precisely after known sources of error were taken into account. "No experiment is decisive in the way that Eddington's experiment was presented as being decisive," says Harry Collins, a sociologist of science at Cardiff University in Wales. Indeed, researchers didn't truly nail the light-bending prediction until they used quasar measurements made in the 1960s, says physicist Clifford Will of Washington University in St. Louis, an expert in tests of general relativity.
Science historians John Earman, then at the University of Minnesota, and Clark Glymour of the University of Pittsburgh, revisited the eclipse study in a 1980 paper, concluding that Eddington had erred by suppressing the clashing Sobral result.
But the historical revision never received much scrutiny, physicist–historian Daniel Kennefick of the University of Arkansas Center for Space and Planetary Sciences in Fayetteville argues. "It's actually like you can see two myths layered on top of each other," he says.
To disentangle them, he dug into the historical record. Letters between Eddington and Dyson indicate that the two analyzed their data separately to avoid influencing each other, Kennefick reports in a recent paper. That means Dyson, who was at first ambivalent about Einstein's theory, made the initial judgment to exclude the 0.93–arc second result. Kennefick documents that Eddington acted properly when Dyson, presumably overeager at the potential discovery, put aside his first instinct and proposed averaging the three measurements to get a value that was closer to Einstein's prediction.
Eddington squelched the idea, because it would have meant giving added weight to the suspect measurement from Sobral. Biased or not, Eddington made the right call, says Kennefick, who discovered that Royal Observatory staff in Greenwich had reanalyzed the Sobral data in 1978 using modern computer-based methods. (The Príncipe data hadn't survived.) Their correction put the 0.93–arc second shift at 1.55 arc seconds, plus or minus 0.34—much closer to the 1.75 value. In other words, the researchers were right to suspect that the measurement was flawed.
"If I was in the same position, I would have done the same thing," says Washington University's Will, who adds that he never believed Eddington had cooked the numbers. "It just didn't seem credible to me that someone of his stature would throw out data because it didn't look right."
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17 Comments
Add CommentOnce again Science is shown to be a vast conspiracy to discredit the account of creation set forth in the Bible. The Relativitivists, like all Scientists, cooked the numbers to back their pet theory. Scientists need Einstein's theory of gravity to be right because it claims nothing can go faster than light; the Scientists use the speed of light to "prove" by the red shift of "receding galaxies" that the universe is 19 billion years old. Think about it: can space really be some kind of vast "grid" that is "warped" by "massive" objects like the sun and moon as Einstein argued? If so, where's the grid? The whole idea is ludicrous. Genesis clearly states that on the 2nd day, 6000 yrs. ago, God created the firmament to divide the waters above from those below, on the 3rd day He created the Earth, and on the 4th day He created the "two great lights" (Sun and Moon) and placed them in the firmament above the Earth. No grid, no space warp, no crazy time effects. Just the One True God. Amen.
Reply | Report Abuse | Link to thisWhat happnes when you cross a radical fundamental Christian with a nutty left wing conspiracy theorist?
Reply | Report Abuse | Link to thisThis post!
I doubt it, there have been too many observations since that have confirmed the theory of relativity
Reply | Report Abuse | Link to thisOne picky point: the stars would appear to be shifted away from the sun, not towards it.
Reply | Report Abuse | Link to thisSecondly, I always felt the data to be a bit dodgy. Fortunately, Eddington was backing the right horse. Hubble's original red-shift data made me feel equally sceptical - was it a feature of the '20s to be so committed to a particular viewpoint?
I don't understand why Einstein is treated as though he were greater than other scientists. He built on the knowledge of those who came before him. Surely others are as bright as he was. I don't think it is fair that he hogs the spotlight and gets special treatment. Many brilliant people play roles everyday that advance our knowledge. They deserve as much credit and attention. Sick of Einstein.
Reply | Report Abuse | Link to thisWe know light has electromagnetic properties. If gravity is simply the distortion of electron dipoles by adjacent matter, then distorting the path of an e.m. light beam is a fairly obvious phenomena. An electrical body, with strong magnetic fields, like the Sun probably has a marked effect on light rays. Who needs a 'mechanical' gravity explanation.
Reply | Report Abuse | Link to thisBUT we now rely on "quasar measurements made in the 1960s," How the heck can a quasar be a better method of making this measurement when we don't really know what or where they are? Quasars may be dimmer than neighbouring bodies (stars) and possess excessive 'redshift' but can we assume what they are? High redshift might be a measure of higher energy levels in proto-galactic formations, if Halton Arp's work is anything to go by. That puts them a lot closer than previously calculated.
In response to Chuck Darwin's response..
Reply | Report Abuse | Link to thisI am afraid that there is not much support for the theory that GOD made the Universe 6000 years ago. Yes there is that old book where many inspired people wrote on topics about everything from psychology to cosmology but these were thoughts of their day using the information at hand at that time. These thoughts were theorizing on how things got started but with the understanding of the universe from their time. It is no longer 4000 BC. The year now is 2008 and we have never before had so much advancement in physics and cosmology as we have in the last few decades. If there is an intelligent omnipotent being watching over us as you think then that being would want you to look around and learn about the universe around you and to question everything.
Response to Buggus56..
Reply | Report Abuse | Link to thisThe bending of the light that they are referring to is specifically due to the mass that the light has while it is not at rest and the mass of the sun. This is what they measured, the gravitational attraction between these two bodies and there have been many other measurements since then that support this. The measurement is more Newton than Einstein.
err, I was joking, of course.
Reply | Report Abuse | Link to this
Reply | Report Abuse | Link to thisPreconception has always had a strong influence on a researchers measurement and expectation. It can even sway or lead the person to a faulty conclusion that seems to be conveniently jiving in with what the person has been looking for. This phenomenon is so deeply rooted in human psychology that it continues to happen.
One could still argue if Sir Eddington, during the 1919 expedition, did indeed intentionally ignore his unfavorable observation in his intense eagerness to prove Einsteins general relativity right. Nonetheless, even if he did, it was still a beautiful slip, confirming Einsteins excellent theory as well as propelling the latter to the pinnacle of the scientific world.
That said, Eddington ought to be given the due respect as a great experimentalist and a right place in the history of science.
(Tan Boon Tee, btt1943@yahoo.com)
As I understand it, Eddington's data was quite scattered. Could the sun's atmosphere have contributed Eddiington's measurements -- of the starlight's deflection? There doesn't seem to be anything mentioned that I can find on this point. Also, what about solar flares and prominences that occur occasionally?
Reply | Report Abuse | Link to thisI understand that Eddington's data was quite scattered. Is it possible that the starlight passed through the sun's atmosphere and that also contributed to the starlight's deflection -- and data scatter? No one that I know of seems to address this issue. Also, what about the possible effect of solar flares and prominences which occur occassionally? Did they occur during Eddington's observations?
Reply | Report Abuse | Link to thisI understand that Eddington's data was quite scattered. Could it be that the sun's atmosphere which can also bend light, contributed to his measures? And, therefore, the bending of light was not only due to the sun's gravity. I have never seen any discussion on this subject. Also, what about the effect of solar flares and prominences which occur occassionally?
Reply | Report Abuse | Link to thisEinstein knew he was playing with fire by assuming all postulates but scientist community was not careful inspite of the fact that equivalence principle had many contradictions. Durgadas Datta tried to justify why Einstein was not correct from the simple fact that --ether or gravitoethertons is very very minute and non reactive except MONO MAGNETIC gravity push AT MOLECULE LRVEL --for our detection in his paper --Misjudgements by NEWTON --published in ASTRONOMY.NET IN YEAR 2002. and links available in --durgadas datta facebook.-- as a result MICHELSONS EXPERIMENR MIS INTERPRETETED.
Reply | Report Abuse | Link to thisGeneral Relativity is, ultimately, a failure. It cannot account for inertia (fundamentally and generally), it cannot account for electromagnetism (electromagnetic phenomena generally), and it cannot account for quantum phenomena (generally and fundamentally).
Reply | Report Abuse | Link to thisGeneral Relativity has to balance attraction and repulsion in order to show: 1) Fundamentally balanced/equivalent gravitational/electromagnetic force (or energy) AND 2) Balanced/equivalent inertia and gravity. It cannot, and does not, do this.
Reply | Report Abuse | Link to thisGravity is key to distance in/of space. Just stand up and look at your feet and the ground. This is exactly what Einstein and the modern physicists are lacking; as distance and force (or energy) have never been shown to be fundamentally equivalent.
Reply | Report Abuse | Link to thisHere is the complete answer and explanation to what Einstein's theory of gravity is lacking:
Space is semi-detached from touch in/as dream experience BECAUSE both inertia and gravity are balanced/equivalent at half strength/force. In outer space, there is [full] inertia, and we cannot touch (and are not touching) objects; and there is no gravity; as this means no experience of touch. Full gravity involves [constantly] touching the earth in our typical earthly experience. Accordingly, touch in dreams may or may not be experienced, and it is also at half force/strength of the tactile, gravitational force/energy while waking and standing. Indeed, we are semi-immobilized in dreams, and this is indicative of half inertia as well. Space manifests as inertial/gravitational/electromagnetic energy in/as dream experience. Full gravity involves full mobility in relation to, and in conjunction with, distance in/of space. Full gravity involves full distance in/of space. The experience of space in/as dream experience is that of the middle distance in/of space in keeping with half gravity and half inertia. Gravity and electromagnetism are key to distance in/of space.
Dreams combine and include opposites; as they fundamentally involve variable and shifting quantum mechanical phenomena/manifestations of what is essentially the same. Completeness and balance go hand-in-hand -- sameness is balanced by variability.