Posted by jlwile on December 10, 2012
More than three years ago, I wrote about the young, faint sun paradox. The problem is fairly simple: Based on everything we know about the thermonuclear reactions that power the sun, it is getting more luminous over time. In other words, the sun is producing more light now (on average) than it did in the past. As a result, the farther you go back in time, the dimmer it should have been. This presents a problem, because the dimmer the sun is, the cooler all the planets (including the earth) are. According to what we know right now, the earth would have been too cold to support life 3.6 billion years ago. Modern paleontology assures us, however, that there was life on earth at roughly that same time.
How do those who believe both modern paleontology and our current understanding of the sun resolve this problem? Unfortunately, the all-too-often response is to deny that there is a problem at all. For example, one old-earth website claims that this used to be a problem, but it has since been solved. It cites a 2010 study1 that merely suggested a possible issue that might reduce the problem. Based on that single study, the website proclaims:
The solving of this paradox provides us with a clear answer that is easily understood, and should eliminate this paradox from being used as evidence of a young earth. Once again, science has prevailed over the claims of young earth creationism.
Of course, nothing could be further from the truth. Indeed, in just over one year, the very same journal published a paper that categorically showed that the solution proposed by the 2010 paper was insufficient. Even giving the proposed solution the widest possible latitude, it fell short of resolving the paradox by a factor of two!2
In fact, this problem is still so difficult to resolve in the old-earth view that the Space Telescope Science Institute hosted a two-day symposium in hopes of starting to find a solution to it.
The symposium was entitled “The Faint Early Sun: Paradox, Problem, or Distraction?,” and in his introduction, here is what Dr. David Soderblom said:
According to standard solar models, at a billion years of age the sun had something like 75% of today’s luminosity, and under those conditions, we would get the earth freezing over and it wouldn’t recover because it would have a high albedo.
In case you don’t understand the word, albedo refers to how much light is reflected from a surface. If the earth really was a frozen ball, it would reflect so much of the sun’s light that even with the conditions we have now, it could not warm itself enough to support life.
So here’s what Dr. Soderblom is saying: If the sun acts the way we think it does, and if the earth/sun interaction wasn’t substantially different in the past, not only would the earth have been inhospitable to life 3.6 billion years ago, it would not even support life today; it would still be a frozen ball. Obviously, then, this is a serious problem for the old-earth view.
In fact, the problem is so difficult that the symposium invited scientists from many disciplines such as astrophysics, geochemistry, and geophysics, to work together to try to solve it. What kinds of solutions were proposed? Well, some proposed that earth’s atmosphere was different from what it is now, although the evidence suggests that it couldn’t have been much different. Others proposed that the earth was actually really cold for a long time and that life only existed in narrow bands around the equator, although that doesn’t seem to square with the fossil data that we currently have. Others proposed that the sun was more massive in the past, but that doesn’t seem to be consistent with what is known about how stars lose mass over time. Others proposed that the earth was closer to the sun back then and has since migrated to its current position, although there are problems reconciling that scenario with today’s structure of the solar system.
In the end, then, it seems that if old-earthers are going to solve this paradox, it will have to be a cross-disciplinary approach. I think Dr. Soderblom said it best near the close of his introductory talk, which is linked above. He thinks the goal of the symposium is to get the participants:
To think about is there a product that we can produce from this meeting…that kind of summarizes the state of knowledge based on what observations and models we have right now and figuring out what are the next steps to try to reign in the parameters of the problem.
In other words, unlike some old-earthers, these scientists recognize that the way the sun changes over time is a serious problem for the old-earth view, and they understand that if there is a solution to the problem, it won’t come quickly or easily. I applaud these scientists for at least recognizing the problem and understanding that they must wrestle with it. Of course, I think they are barking up the wrong tree; I don’t think the earth or the sun existed a billion years ago. Nevertheless, it will be interesting to see what (if anything) comes out over the next few years as a result of this symposium.
1. Minik T. Rosing, Dennis K. Bird, Norman H. Sleep, Christian J. Bjerrum, “No climate paradox under the faint early Sun,” Nature, 464:744-747, 2010
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