Claim CE311:

According to standard models of the sun, the sun's luminosity has increased by 40 percent since the origin of the earth (the "faint young sun paradox"). This would mean that the early earth could not have supported life. Thus an old earth is impossible; the earth must be young.

Source:

Faulkner, Danny, 1998. The young faint sun paradox and the age of the solar system. Impact 300 (June). http://www.icr.org/index.php?module=articles&action=view&ID=429

Response:

  1. The change in luminosity is not as drastic as it sounds. Much of the change would have occurred before the origin of life; the luminosity increase since the origin of life is about 25 percent. And this translates to a 7 percent increase in temperature when the earth's heat outflow is taken into account.

  2. The 7 percent change described above assumes no feedback system, but the earth's climate feedback systems are complex. In particular, the greenhouse effect and albedo could moderate the temperature further. On the early earth, it is likely that greenhouse gases such as carbon dioxide and methane were commoner than they are today.

  3. Life has survived fairly large changes in climate over its history, from a near-global glaciation in the late Precambrian, to a global temperature warmer than today's in the Carboniferous.

Links:

Johansson, Sverker, 1998. The solar FAQ. http://www.talkorigins.org/faqs/faq-solar.html
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created 2003-5-17