Apr 26 2012

The Faint Young Sun Paradox

Earlier this week I wrote about paradoxes in science, about how they are good things pointing the way toward new research and possibilities. Science deniers, however, exploit them to cast doubt on established science, without creating a viable scientific theory of their own. I gave as an example the solar neutrino problem – the fact that in the 1980s and 1990s neutrino detectors were detecting 1/3 to 1/2 the solar neutrinos than the standard model of particle physics predicted. Creationists used this to argue that the entire nuclear fusion model of stars was wrong.  It wasn’t long, however, before the missing neutrinos were discovered and the paradox resolved.

Recently I was asked about another sun-based paradox that creationists use to argue for a young earth – the faint young sun paradox. This was first pointed out by Carl Sagan and George Mullen.  Our models of stellar evolution indicate that the sun has been getting steadily brighter and hotter over the last four billion years. As hydrogen is fused into helium and helium therefore builds up on the core of the sun, it has to burn a little hotter in order to maintain equilibrium. The sun is burning about 30% hotter today than it was four billion years ago.

The sun is the major source of heat for the earth’s surface, and therefore a colder sun in the past would mean that the earth was colder, by about 25 °C.  By this factor alone the earth should have been mostly a ball of ice and snow up until 1-2 billion years ago. However the geological evidence points strongly to there being liquid water on the earth even when it was young.

There is the paradox – stellar models tell us the early earth was too cold for liquid water, but geological evidence tells us there was liquid water on the early earth. Paradoxes point the way to new information that will both resolve the paradox and improve our understanding of the universe. When two pieces of scientific information conflict that standard resolution is that either one or both pieces of information are incorrect, or there is a missing piece of information that changes the picture.

So – one way to resolve this paradox is to argue that our models of stellar evolution are incorrect. Perhaps the early sun was not colder than the current one. These stellar models, however, are rooted in fairly solid physics and astronomical observation. It seems unlikely at this point that they are far off from reality. However there is a hypothesis that the early sun had more mass and that this compensated for the other factors, resulting in an early sun that was hot enough to account for a warm earth.   The second way is to question the geological evidence for a warm early earth. There are multiple independent lines of evidence for liquid water on the early earth, however, including sedimentary rocks, mud cracks and ripples, and algae.

The paradox, by the way, also holds true for Mars. Mars also would have been cooler due to a fainter young sun. There is also evidence for liquid water on the early Mars. Solutions to the paradox that affect the entire solar system would resolve it for both planets. If the solution is planet specific, however, then each planet would require its own solution.

If both our stellar models and the evidence for a warm early earth are fairly solid, then we must consider a third possibility – that there is some other factor at work that can resolve the apparent paradox. The standard hypothesis is that the atmosphere of the early earth was different than it is now in a manner that would increase the greenhouse effect and result in a warmer earth despite a cooler sun. This seems like an obvious enough solution. Carbon dioxide, ammonia, and methane are all powerful greenhouse gases and may have been present in larger amounts in the early atmosphere. Life did radically change the composition of the earth’s atmosphere, introducing oxygen, for example. The net effects, however, still need to be sorted out.

A related hypothesis not involving greenhouse gases is that the early earth had a lower albedo, meaning that it absorbed more energy from the sun. This could be due to a darker ocean and/or less cloud cover. (The cloud cover hypothesis has recently been refuted, however.) There are also other minority hypotheses, such as the cosmic ray hypothesis. Cosmic rays may have a cooling effect on the earth, and the early sun may have shielded the earth from more of these cooling cosmic rays.

A recent study of fossilized raindrop impressions in volcanic ash suggests that the atmosphere was not thicker billions of years ago. This means that a thicker total atmosphere is likely not the solution to the faint young sun paradox. This was not really a major hypothesis in any case, and I am also not sure how definitive this raindrop evidence is. It is just one more bit of data in the complex story of this paradox.

Young earth creationists, however, have been quick to pounce on this study to “paradox monger.” The Institute for Creation Research recently published an article called, “Ancient Raindrops Argue for Young Earth.” I’m not sure if the irony of this headline is lost on them or not, but I am pretty sure they don’t care. All they do care about is that there is a paradox, and they can exploit that to sow doubt about scientific findings they find inconvenient. They cannot help, however, to hopelessly contradict themselves.

The apparent paradox results from sciences that also point to an ancient earth, solar system, and universe. The same stellar models that create the paradox also point to a sun that is billions of years old. The same fossil evidence that points to a warm early earth also points to an ancient earth. Creationists, however, want the paradox without the underlying science, resulting in a self-contradicting mess of an argument. They are not interested, however, in creating a viable theory. They just want to poke apparent holes in established science.

I don’t know what the solution to the faint young sun paradox will turn out to be. There are many viable hypotheses, but we simply lack definitive information to know which one or ones are correct. That’s science. This controversy will rage for a while, but if history is any guide eventually we will sort out what the correct resolution is.

15 responses so far

15 Responses to “The Faint Young Sun Paradox”

  1. ccbowerson 26 Apr 2012 at 9:20 am

    “The Institute for Creation Research recently published an article called, ‘Ancient Raindrops Argue for Young Earth.’”

    Yes. These 2.7 billion year old fossilized imprints of rain are clear evidence that the earth is less than 6,000 years old.

  2. CWon 26 Apr 2012 at 10:00 am

    Maybe I’m confusing theories, but doesn’t heat from radioactive decay help explain how the Earth could’ve been warm enough to have liquid water?

  3. roadfoodon 26 Apr 2012 at 10:58 am

    Let me get this straight: One line of solid scientific evidence and reasoning indicates that the sun was too cool 4 billion years ago to heat the Earth enough to allow liquid water. Another line of solid scientific evidence indicates that there nevertheless was liquid water on Earth 4 billion years ago. Therefore, the Earth must be only 6,000 years old. Yup, and my cat has fur, therefore chickens can’t fly. Makes perfect sense to me . . .

  4. SARAon 26 Apr 2012 at 11:47 am

    When I was a teenage fundamentalist I went to several lectures on creation vs evolution. I remember being quite impressed while he talked about all his scientific evidence for bibilical creation. I was predisposed to believe him, so I wasn’t looking for reasons not to.

    Still, I recall two things though that really made me skeptical of his ideas the more I considered them later.
    A. He insisted carbon dating was inaccurate and that scientists the world over were fools to continue using it.
    B. He said that there was no rain at all before Noah’s ark. That water came out of the ground every morning like dew but rather more of it. I don’t quite recall how, but this explained the different levels of strata in geology, I think.

    The second in particular is what made him lose me. I suppose, looking back, I should thank him for being one of the early builders of my loss of faith and my ability to accept a world that wasn’t easily and simply explained.
    However, I doubt mine is the typical experience of a young mind being introduced to such “theories” as the creationist’s tout.

  5. locutusbrgon 26 Apr 2012 at 1:11 pm

    Now you have made me wonder about the competing theories that actually explain this. Some solar coronal issue?

  6. SteveAon 26 Apr 2012 at 2:13 pm

    SARA: ‘He said that there was no rain at all before Noah’s ark.’

    Do you know why he thought this? Does pre-deluge rain fly in the face of scripture somehow?

    As a side note, I never understood why young earthers are so keen to show how dinosaurs could have been carried on Noah’s ark. Was it just because they ‘must’ have been around so they must have been taken on board alongside everything else. Okay. So what happened to them after that?

  7. SARAon 26 Apr 2012 at 2:43 pm

    I really don’t know why he thought that. This was several decades ago but I think it was an alternate theory based on some “science” rather than anything in bible. I could be remembering wrong though.

  8. sowellfanon 26 Apr 2012 at 3:03 pm

    @Sara & @SteveA:

    I googled a bit and found an explanation over at “Answers in Genesis”. Apparently:

    Genesis 2:5–6 states that “the LORD God had not caused it to rain upon the earth, and there was not a man to till the ground. But there went up a mist from the earth, and watered the whole face of the ground”.

    Apparently there are people that believe that this indicates that there was no rain until the time of the flood, only mist. But the AIG people say that this specific verse only addresses the 6-day creation period, and that after that time it’s completely reasonable to guess that there was rain (though apparently the bible doesn’t address it either way). So, it’s another fun little doctrinal fight.

  9. robmon 26 Apr 2012 at 4:13 pm

    As a side note, I never understood why young earthers are so keen to show how dinosaurs could have been carried on Noah’s ark.

    There are a couple of reasons, Noah was supposed to take 2 of every animal, so dinosaurs would have to be there. The bible describes monsters, many of which could fit the description of a dinosaur, and finally some crazy people double down and own their crazy.

    As for what happened later, creationists give a hand waving explanation that they were all hunted to extinction.

  10. bgoudieon 26 Apr 2012 at 4:55 pm

    I always love when it the young earthers start in on the great amounts of water in the firmament before the flood and how these blocked cosmic rays, thus allowing people to live to the great ages recorded in the Bible.

  11. Watcheron 27 Apr 2012 at 12:03 pm

    As a side note, I never understood why young earthers are so keen to show how dinosaurs could have been carried on Noah’s ark.

    It’s a paradox of their own that theyre trying to explain. But it’s one theyre OK with.

  12. Dirk Steeleon 28 Apr 2012 at 8:54 am

    There are a couple of other explanations for the sun paradox that I find entertaining.

    One is from David Deutsch’s book Fabric of Reality which says that physics must take into account the prospect of advanced technological life forms being able change what we observe. Perhaps some thetans altered the sun before seeding the earth with a few microbes.

    The second is the possibility we live in a simulated universe. . . as proposed by Nick Bostrom, Faculty of Philosophy, Oxford University.


    and that the programmer had to make a little tweak to his algorithms. I have followed digital physics stuff from the days of Konrad Zuse and Ed Fredkin but now I suffer from Mathematical Defficiency Disorder, MDD, and can’t keep up with the physics of today. And the drugs don’t work… 🙁

  13. lelieon 10 Jul 2012 at 1:12 pm

    I’ve been doing other parts of physics for the last few decades, but I think I have a question that needs to be injected into this conversation. The ‘Faint Young Sun’ also opens up other cans of worms. 70% at 1 billion years, and heating gradually until now, or an approximation of that, right? Enter carbon 14 dating. The way they explained the system when I did nuclear 35+ years ago, most carbon 14 was created by low energy cosmic ray bombardment from our local star. http://www.physics.mcgill.ca/~mccutchm/Papers/Hess_1959.pdf High energy rays don’t come from our sun, but they don’t interact with atmospheric carbon much either. I guess that’s still in vogue (http://www.numericana.com/answer/nuclear.htm#radiocarbon) So, we have a star making less neutrons, ergo less C14 production, which means less C14 in the systems of plants, or things that eat them, etc. At some point, we have to change the assumed distribution of C14 to C12 due to decay, because the system has not been uniform for the entire time. In other words, we need a new ‘fudge factor’ for carbon dating due to changes in low energy neutron production from the sun at each earlier date. It won’t be a big factor, at least not for the last few million years, and certainly doesn’t influence the dating of the sun, but I don’t think it can be ignored for all these nice carbon systems we find. All that is needed is the low energy neutron production as a function of time for the last few hundred million years, and the rest is an exercise for the student. Either that or a definitive demonstration that carbon dating is independent to a high order of low energy cosmic rays.

    Larry Elie

  14. Thadiuson 01 Aug 2012 at 2:30 am

    “So, we have a star making less neutrons, ergo less C14 production, which means less C14 in the systems of plants, or things that eat them, etc”

    Carbon 14 dating is only used for 58,000-62,000 years back, so no problem man.

  15. nixb25on 24 Sep 2012 at 4:42 pm

    “I always love when it the young earthers start in on the great amounts of water in the firmament before the flood and how these blocked cosmic rays, thus allowing people to live to the great ages recorded in the Bible.”

    I always love it too! I never realized this explanation until a professor taught it to me in college. And as far as dinosaurs on the ark goes, we know that reptiles grow larger throughout their lives. If people could live to be over 900 before the flood, then why not dinosaurs too? But a young adult brachiosaur needn’t be much larger than a dog or at most a horse…

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