A Response to the Shrinking Sun Argument
8. Since 1836, over 100 different observers at the Royal Greenwich Observatory and the U.S. Naval Observatory have made direct visual measurements which show that the diameter of the sun is shrinking at a rate of about .1% each century or about 5 feet per hour! Furthermore, records of solar eclipses infer that this rapid shrinkage has been going on for at least the past 400 years (a). Several indirect techniques also confirm this gravitational collapse, although these inferred collapse rates are only about 1/7th as much (b-c). Using the most conservative data, one must conclude that had the sun existed a million years ago, it would have been so large that it would have heated the earth so much that life could not have survived. Yet, evolutionists say that a million years ago all the present forms of life were essentially as they are now, having completed their evolution that began a thousand million years ago.
a)"Analyses of Historical Data Suggest Sun is Shrinking," Physics Today, September, 1979, pp. 17-19.
b) David W. Dunham, et. al., "Observations of a Probable Change in the Solar Radius Between 1715 and 1979," Science, Vol. 210, December 12, 1980, pp. 1243-1245.
c) Irwin I. Shapiro, "Is the Sun Shrinking?", Science, Vol. 208, April 4, 1980, pp. 51-53.
The original source for all this was an abstract presented at a meeting of the American Astronomical Society in 1979, "Secular Decrease in the Solar Diameter, 1836-1953" by John Eddy & Aram Boornazian. It didn't take long to hit the creationist press: Impact 82 - "The Sun is Shrinking" by Russell Akridge. Reference "a" above is an article by Gloria Lubkin in the news section of Physics Today, reporting the presentation by Eddy & Boornazian. This is repeated in the body of Impact 82. But you will note that there is no reference to Eddy & Boornazian in the list of references at the end of Impact 82. That's because they never published the paper, and later retracted their own results, a minor point that seems to have escaped the creationist gaze all these years.
Impact 82, which constitutes the basis for this argument in creationist circles, makes two severe mistakes. First, the unwarranted presumption that the Eddy & Boornazian result was a done deal, a finished fact. Indeed, in reality it was a result so tentatiive that it never survived beyond the stage of a meeting abstract. Second, the even more unwarranted assumption that, if true, the rate of shrinkage suggested must have been constant over all times past. This is a result of the standard, but quite false, creationist notion that evolutionists are uniformitarians in some strange and literal sense that has never been seen in reality.
So, the bottom line rests on two question: (1) Is the sun systematically shrinking or not? (2) What about all those eclipse records mentioned above, don't they show the sun shrinking?
The answer to (1) is definitely not. Brown & Christensen-Dalsgaard, 1998, carried out a detailed study of the solar photospheric radius over a six year time frame, from 1981-1987. Their results imply a constant solar radius, within a measurement error of +/- 37 kilometers (km) over the whole 6 years. If the solar radius were in fact shrinking by 5 feet per hour, that translates into 37 km in about 2.8 years. That would impose a greater than 2-sigma systematic trend on the six year data set, an effect the proverbial blind man could hardly miss.
And to make problems even bigger, there is some evidence that the sun
actually expands periodically. E. Ribes analyzed a 53 year record of solar
diameter & sunspot positions, taken during the 17th century. He shows that
the sun was in all probability larger, and rotating more slowly, during
the famous Maunder minimum in the sunspot cycle. More recently,
observations carried out at the San Fernando Solar Observatory show the
sun expanding and contracting significantly, over the roughly eleven year
solar cycle. In any case, it is quite certain that today, no such
systematic decrease in solar radius is happening.
[Since writing this I have been in personal communication with the director of the San Fernando Solar Observatory, who tells me that he now believes the effect to be about an order of magnitude smaller than was originally thought].
But what about the past, and question (2)? The answer there is most likely the same - no shrinking. A recent study out of the Observatoire de Paris reached back and re-analyzed 300 years of eclipse and solar diameter observations. But this time a careful study of the instruments used was carried out, in order to determine the true instrumental errors. The corrected re-analysis removes all doubt: the reported shrinking was spurious, the result of unanticipated instrumental uncertainties.
And so another young-earth argument is laid to rest. The sun is not now shrinking, and has not done so over the last 300 years.
Brown, T.M. & J. Christensen-Dalsgaard
"Accurate Determination of the Solar Photospheric Radius"
Astrophysical Journal Letters, 500(2)Part2: L195-L198 (1998 June 20)
"Evidence for a larger sun with a slower rotation during the 17th century"
Nature, 326(6108): 52-55 (1987)
Ribes, E.; J.C. Ribes & R. Barthalot
"Solar Diameter and Solar Rotation During the Maunder Minimum"
IAU Symposia, (123): 227-230 (1988)
"The Diameter of the Sun Over the Past 3 Centuries"
Astronomy and Astrophysics, 325(3): 1174-1178 (1997 Sep)
Is the Sun Shrinking? - From the Stanford Solar Center FAQ
Dave Matson on the Shrinking Sun Argument