Perry, Kelvin, and the age of the sun
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Lord Kelvin argued that the Sun had to be between 20 and 100 million years old, based on the assumption that the Sun’s energy source was gravitational contraction. As everyone now knows, the Sun’s actual power source is the thermonuclear fusion of hydrogen into helium. But Kelvin’s number is based on a physical assumption for which he could give no justification: the Sun’s density is approximately constant. Had Kelvin assumed instead that the Sun had a small core near a black hole radius – an assumption allowed by the knowledge of physicists at the end of the nineteenth century – he would have obtained an age for the Sun as long as 10 trillion years, completely consistent with the long time scale required for evolution. Conversely, had Kelvin accepted the geologists’ time scale, he would have been forced to acknowledge the existence of very dense objects, making it easier for twentieth century astronomers to accept the existence of black holes and neutron stars.
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- 1.Birchfield, J.D. 1975. Lord Kelvin and the Age of the Earth (New York, Science History Publications) Google Scholar
- 2.Chandrasekhar, S. 1957. Introduction to the Study of Stellar Structure (New York, Dover) Google Scholar
- 3.England, Ph., P. Molner, F. Richter 2007a. John Perry’s Neglected Critique of Kelvin’s Age for the Earth : A missed Opportunity in Geodynamics. GSA Today 17: 4-9 Google Scholar
- 4.England, Ph., P. Molnar, F. Richter 2007b. Kelvin, Perry, and the Age of the Earth. Am. Sci. 95: 342-349 Google Scholar
- 5.Helmholtz, H. von. 1961. On the Interaction of the Natural Forces, reprinted in Popular Scientific Lectures, edited by M. Kline (New York, Dover) Google Scholar
- 6.Kelvin, W. Thomson, Lord. 1862. On the Age of the Sun’s Heat. Macmillan’s Magazine 5: 388-393 Google Scholar
- 8.Laplace, P.S. de 1796. Exposition du Systême du Monde (Paris, de l’Imprimerie du Cercle-Social, rue du Thaéˆtre Français, l’an IV de République Française), Vol. 2, p. 305 Google Scholar
- 9.Laplace, P.S. de 1799. Proof of the theorem, that the attractive force of a heavenly body could be so large, that light could not flow out of it. Reprinted as Appendix A in Stephen W. Hawking, George F.R. Ellis 1973. The Large Scale Structure of Space-Time. Cambridge University Press, Cambridge, pp. 365–368. Original article published in Allgemeine geographische Ephemeriden herausgegeben von F. von Zach iv Bd. 1st., 1 Abhandl., Weimar Google Scholar
- 10.Michell, J. 1784. On the means of discovering the distance, magnitude, etc. of the fixed stars, in consequence of the diminution of the velocity of their light, in case such a diminution should be found to take place in any of them, and such data should be procured from observations, as would be farther necessary for that purpose. Philos. Trans. 74: 35-57 CrossRefGoogle Scholar
- 11.Perry, J. 1895a. On the Age of the Earth. Nature 51: 224-227 Google Scholar
- 16.Tipler, F.J. 1994. Physics of Immortality (New York, Doubleday) Google Scholar
- 18.Zeldovich, Ya.B., I.D. Novikov 1971. Relativistic Astrophysics, in Stars and Relativity (Chicago, University of Chicago Press), pp. 337–338 Google Scholar