Young-earth "proof" #1:  The sun is shrinking at 5 feet/hour which limits the earth-sun relationship to less than 5 million years.

The shrinking sun argument contains two errors.  First, and by far the worst, is the assumption that if the sun is shrinking today, as might be determined over a period of years, then it has always been shrinking!

That's a little like watching the tide go out and assuming that the water level must have always been going down at that rate.  In order for that to be true, much of the land must have been flooded mere weeks ago!  Inasmuch as the earth shows no signs of such a flood we conclude that the earth can't be older than a few weeks!

Obviously, we cannot extend a rate willy-nilly.  We do have to take into account the physical nature of the system.  The fact that the tide is going out doesn't mean that it can't come back in!  Just as obvious, at least to the experts if not to yourself, is the fact that our sun could never have undergone a long period of continuous shrinking as described by the creationists.  Such a view totally ignores the forces at work within our sun.  Infinitely more likely is the possibility that our sun might alternate between small periods of shrinking and small periods of expansion, a kind of oscillation.  Indeed, some scientists believe that there may be an 80 day cycle of slight shrinking and expanding.

Over billions of years, of course, the depletion of the sun's hydrogen will upset the sun's internal balance and the sun will undergo some continuous changes. But, that has absolutely nothing to do with the shrinking sun argument above which attempts to prove that the solar system is less than 5 million years old.

Thus, the shrinking sun argument rests squarely on a naive extension of a rate measured over a relatively short period of time.  It's the type of blunder one would hope not to find in a high school science project.

The second error is the assumption that the claimed rate of shrinkage in the study by Eddy and Boornazian is an established fact.  In fact, serious flaws in their methodology turned up and the data has been discredited.  As a result, the full text of their study was never published.  

Some creationists, such as Walter Brown, have tried to keep the argument going by quoting additional sources (Lippard, 1990, p.25), but they have not passed the test.  In Brown's case, two of the three sources he offered were obsolete, and the third actually undercut his position (Lippard, 1990, p.25)!  In a rebuttal to Lippard, Walter Brown offered no new studies to back up his "feeling" that the sun is undergoing a small, but continuous shrinkage (Brown, 1990, pp.45-46).  

Brown, in his debate with Lippard, then dodged into the missing neutrino problem in a vain effort to turn it into evidence for his position. However, no support can be had there unless it is demonstrated that the "missing" neutrinos are due to a corresponding lack of fusion, and that the sun's current output of energy is due, in large part, to gravitational collapse. As there are several possible solutions to the missing neutrino problem (Lippard, 1990a, p.32), Brown's scenario is an extremely tall order. Even if it were proved that there is a deficiency in solar fusion, that being the cause of the missing neutrinos, Brown would still have to prove that the situation was permanent. It could be a temporary glitch or even part of some complex cycle. Thus, any attempt at present to use the missing neutrino problem as support for a shrinking sun is wholly misguided.

It was in 1979 that astronomers John Eddy and Aram Boornazian presented a paper and published its abstract: "Secular Decrease in the Solar Diameter, 1836-1953." In the April 1980 issue of ICR's Impact series (Impact #82), Russell Akridge picked up the report and naively extended the shrinkage rate of 5 feet/hour into the indefinite past. As that soon led to an impossible situation, he concluded that the earth was much less than 20 million years old. Soon, Walter Brown, Thomas Barnes, Henry Morris, Hilton Hinderliter, James Hanson, and other creationists were in on the act, and the shrinking sun argument became a part of creationist legend.

A number of studies have not found any evidence for continuous shrinking in the sun. Leslie Morrison, for example, drawing on Edmund Halley's observations of the solar eclipse of 1715, concluded that there is no evidence that the sun is shrinking. His findings were reported in January, 1988 in Gemini (no.18, pp.6-8). Gemini is the official journal of the Royal Greenwich Observatory.

Thomas Barnes, Walter Brown, and Henry Morris used the argument for several years after the original report by Eddy and Boornazian was discredited (Till, 1986). I guess a lot of creationists still haven't gotten the word. In his debate with Dr. Paul Hilpman, on June 15, 1992 at the Royal Hall of the University of Missouri, Dr. Hovind applied the obsolete shrinking sun argument.

Isolated from the corrective of continuing professional investigation and evaluation, the 'creation-science' community continues to employ this unwarranted extrapolation of a discredited report as 'scientific evidence' for a young Earth. (Van Till, 1986, p.17)

That was true in 1986 and is true today; it will be true for years to come. "Scientific" creationism lives like the proverbial ostrich, with its head in the sand, and has no effective mechanism to weed out error.