wa301@sdcc12.UUCP (wa301) (07/03/85)
[ rck@iham1.UUCP (Ron Kukuk), 25 Jun 85 17:07:20 GMT ] > 52. If the sun, when it first began to radiate, had any > nonnuclear sources of energy, they would have been > depleted in much less that ten million years. Theory [a] > and experiment [b] indicate that today nuclear reactions > are not the predominant energy source for the sun. Our > star, the sun, must therefore be young (less than ten > million years old). If the sun is young, then so is the > earth. > > a) A.B. Severny, V.A. Kotov, and T.T. Tsap, NATURE, > Vol. 259, 15 January 1976, pp. 87-89. > b) Paul M. Steidl, ''Solar Neutrinos and A Young Sun,'' > in DESIGN AND ORIGINS IN ASTRONOMY, edited by George > Mulfinger, Jr. (Norcross, Georgia: Creation Research > Society Books, 1983), pp. 113-125. I have seen this argument before in the chapter entitled, "Is the solar system really 4.5 billion years old?", in the book, "Reasons Skeptics Should Consider Christianity", by Josh McDowell and Don Stewart (Here's Life Publishers, 1981). It goes like this: 1) In 1850, von Helmholtz proposed that the sun's thermal energy comes from its gravitational collapse. The chapter cites modern-day astronomer George Abell, who says that the sun's age would be of the order of 100 million years, according to von Helmholtz's proposal. 2) Later on (in the 1920's), scientists learned about nuclear fusion and decided that all stars get basically all of their thermal energy from fusion, not from gravitational collapse. 3) Later still, astronomers made more detailed models of the sun, and they predicted a certain value for the amount of neutrinos emitted by the sun's nuclear reactions. (The chapter uses the unusual spelling "nutrino".) 4) Recent experiments have measured the solar neutrino flux and found it to be much less than that predicted in 3). 5) Therefore, the hypothesis of 2), that the sun shines by fusion, must be wrong. 6) Recent observations cited by the chapter show that the sun has been shrinking for at least 400 years. 7) Therefore, the hypothesis of 1), that the sun shines by gravi- tational collapse, must be correct, and the sun is much younger than 4.5 billion years. At the time I first read this argument, it was my impresssion that solar fusion was a well-established fact, not merely a hypothesis in competition with the pre-relativity hypothesis of gravitational collapse. Several months later, in June 1983, I had the opportunity to bring this chapter to the attention of Dr. Abell himself, and I asked him if it had any validity. He said: a) The accuracy of the solar neutrino measurements is pretty well accepted. The theory in 3) makes an incorrect prediction. b) Solar physicists are busily working to find out why their model is wrong. However, the predicted neutrino rate is very sensitive to the value of certain parameters in the model. A small adjust- ment of these parameters yields the observed value of the neutrino rate. This adjustment does NOT contradict the basic fact of solar fusion. Argument 52 is invalid.
ethan@utastro.UUCP (Ethan Vishniac) (07/10/85)
> > b) Solar physicists are busily working to find out why their model > is wrong. However, the predicted neutrino rate is very sensitive > to the value of certain parameters in the model. A small adjust- > ment of these parameters yields the observed value of the neutrino > rate. This adjustment does NOT contradict the basic fact of > solar fusion. One more point, the solar neutrino experiment measures the flux of high energy neutrinos. These neutrinos are *not* produced in the fusion of hydrogen into helium, but rather in a single, energetically unfavorable, reaction involving a chain of reactions that result from adding protons onto helium. As a result there is a simple way to modify the standard model to eliminate these neutrinos. *Any* mechanism which flattens the temperature profile in the sun's core will do. A more conclusive test would be to look for lower energy neutrinos produced during the p-p chain. These neutrinos are the inevitable result of fusion. The experiment is possible, but expensive. It will be done eventually. If the shortfall persists there will be just two possible explanations. First, the sun doesn't steadily produce, through nuclear fusion, as much energy as it puts out. Second, neutrinos have mass and the "electron" neutrino is not a fundamental particle but a coherent superposition of neutrinos of different masses. The second possibility *might* be testable in the laboratory. -- "Don't argue with a fool. Ethan Vishniac Borrow his money." {charm,ut-sally,ut-ngp,noao}!utastro!ethan Department of Astronomy University of Texas