There is No Scientific Training Which Can Guard Against the Desire to Obtain a Particular Result / The History of Science Records a Number of Significant Examples Where the Entire Scientific Community Falls Prey to a Common DelusionUnexpected: Parallax is Very Small Because Stars Are Farther Away than Expected
From William Broad and Nicholas Wade, "Self-deception and Gullibility," Betrayers of the Truth
(New York, 1982), pp. 107-108"In 1669, the distinguished English physicist, Robert Hooke, made a wonderful discovery. He obtained the long-sought proof of Copernicus' heliocentric theory of the solar system by demonstrating stellar parallax -- a perceived difference in [the] position of a star due to the Earth's motion around the Sun. One of the first to use a telescope for this purpose, Hooke observed the star Gamma Draconis and soon reported to the Royal Society that he had found what he was looking for: The star had a parallax of almost  seconds of arc. Here, at last, was impeccable experimental proof of the Copernican theory.This heartening triumph of empirical science was only momentarily dashed when the Frenchman, Jean Picard, announced he had observed the star Alpha Lyrae by the same method but had failed to find any parallax at all. A few years later, England's first Astronomer Royal, the brilliant observer, John Flamsteed, reported that the Pole Star had a parallax of at least  seconds.Hooke and Flamsteed, outstanding scientists of their day, are leading lights in the history of science. But they fell victim to an effect that, to this day, has continued to trap ... scientists in its treacherous coils. It is the phenomenon of experimenter expectancy, or, seeing what you want to see. There is, indeed, a stellar parallax, but, because of the vast distances of all stars from Earth, the parallax is extremely small -- about  second of arc. It cannot be detected by the relatively crude telescopes used by Hooke and Flamsteed.Self-deception is a problem of pervasive importance in science. The most rigorous training in objective observations is often a feeble defense against the desire to obtain a particular result. Time and again, an experimenter's expectation of what he will see has shaped the data he recorded to the detriment of the truth. This unconscious shaping of results can come about in numerous, subtle ways. Nor is it a phenomenon that affects only individuals. Sometimes a whole community of researchers falls prey to a common delusion ....Expectancy leads to self-deception, and self-deception leads to the propensity to be deceived by others."Also Unexpected: Parallax is Only Accurate to 1% the Diameter of the Milky Wayhttp://www.thunderbolts.info/eg_draft/eg_chapter_1.htm"Triangulation, or trigonometric parallax, is a direct way of using the measured angular difference from two positions to measure the distance to some object. By observing a star's position relative to the background stars from opposite sides of our orbit about the Sun, we have a wide baseline that will allow us to get an angular difference from observations 6 months apart and be able to measure the distance to something as far away as a star.The Earth averages about 93 million miles from the Sun, so that is its nearly-circular orbit's radius. This distance is often called an astronomical unit (AU) in astronomy. So the distance from one side of the Earth's orbit to the opposite side is 2 AU, or about 186 million miles. When we measure the angle to the nearest star (Alpha Centauri) from one side of the orbit, wait six months, and measure it again, we find that the angular difference is rather small, requiring enormous precision of measurement ...The European Space Agency (ESA) launched its automated Hipparcos satellite telescope to take measurements of over 118,000 stars during its lifetime from 1989–1993. Mission: improve the precision of catalogued locations of many stars and update the Tycho and Tycho 2 catalogs. Out of the newly measured parallaxes, 20,870 stars met the criterion of having 10% or less stellar parallax error.Even with the more accurate Hipparcos satellite data, distance measurements to stars out to around 200-220 light-years have up to 10% error, and they are increasingly less accurate out to about 500 light-years. Beyond that, trigonometric parallax measurements should not be considered reliable. Pogge, in the link above to his Lecture 5, claims Hipparcos data give "good distances out to 1000 light-years", yet an estimated distance of only 500 light years with ±20%–30% error is already off by too much to be of much use. 1000 light-years is an almost incomprehensible distance, yet it is only about 1% of the way across our Milky Way galaxy.
(assuming, of course, that we've correctly identified the diameter of the Milky Way)There Have Been Many Instances Where Expectations Led the Entire Scientific Community Astray
Some of the more well-known examples ...
1. The maser, the laser's precursor, was originally thought by the most respected quantum theorists of the day to be impossible. See the story here: https://plus.google.com/108466508041843226480/posts/PpwuZ24rTgQ
2. When radio waves were first observed from space by radio engineers
, they were assumed by astronomers
to be either a hoax or a mistake. Learn the history here: https://plus.google.com/108466508041843226480/posts/AFh4Q5Ceggb
3. When Robert Goddard, the inventor of the rocket, suggested that science fiction books were right -- that we could indeed go to the Moon with rockets -- he was ridiculed for not knowing that a rocket would have nothing to push against in space (his critics obviously not understanding Newton's laws of motion). This ridicule continued virtually all the way up to the point that that the Nazis were raining ICBMs down upon London in 1944. See that incredible story here: https://plus.google.com/+ChrisReeveOnlineScientificDiscourseIsBroken/posts/Jgikude95Wa #science #bias #parallax