Darwin vs. the Sun


Today, we take it for granted that the Sun produces energy via nuclear fusion. However, this realization only came about in the early 1900’s and wasn’t confirmed until several decades later (see the Solar Neutrino Problem). Prior to that, several other methods of energy production had been proposed. These ranged from burning coal to a constant bombardment of comets and meteors to slow contraction. Each of these methods seemed initially plausible, but when astronomers of the time worked out how long each one could sustain such a brightness, they came up against an unlikely opponent: Charles Darwin.

In a “Catholic Magazine and Review” from 1889, known as The Month, there is a good record of the development of the problem faced in an article titled “The Age of the Sun and Darwinism”. It begins with a review of the recently discovered Law of Conservation of Energy in which they establish that a method of generation must be established and that this question is necessarily entangled with the age of the Sun and also, life on Earth. Without a constant generation of energy, the Sun would quickly cool and this was known to be unlikely due to archaeological evidences which hinted that the Sun’s output had been constant for at least 4,000 years.

While burning coal seemed a good candidate since coal power was just coming into fashion at the time, scientists had calculated that even burning in pure oxygen, the Sun could only last ~6,000 years. The article feared that this may signal “the end of supplies of heat and light to our globe would be very near indeed” since religious scholars held the age of the Earth to be some “4000 years of chronological time before the Christian era, and 1800 since”.

The bombardment hypothesis was also examined explaining that the transference of kinetic energy can increase temperatures citing examples of bullets striking metal surfaces or hammers heating anvils. But again, calculations hinted that this too was wrong. The rate with which the Sun would have to accumulate mass was extremely high. So much so that it would lead to the “derangement of the whole mechanism of the heavens.” The result would be that the period of the year over the past ~6,000 years would have shortened by six weeks and that the Earth too would be constantly bombarded by meteors (although some especially strong meteor showers at that time lent some credence to this).

The only strong candidate left was that of gravitational contraction proposed by Sir William Thomson (later Lord Kelvin) and Hermann von Helmholtz in a series of papers they began publishing in 1854. But in 1859, Darwin published the Origin of Species in which he required an age of at least two billion years. Thomson’s and Helmholtz’s hypothesis could only support an age of some tens of millions of years. Thus astronomy and biology were brought head to head. Darwin was fully aware of this problem. In a letter to a friend, he wrote that, “Thomson’s views of the recent age of the world have been for some time one of my sorest troubles”.

To back the astronomers was the developing field of spectroscopy in which they determined that the sun and other stars bared a strong similarity to that of nebulae. These nebulae could contract under their own gravity and as such, provided a natural establishment for the formation of stars, leading gracefully into the contraction hypothesis. Although not mentioned in the article, Darwin did have some support from geologists like Charles Lyell who studied the formation of mountain ranges and also posited an older Earth.

Some astronomers attempted to add other methods in addition to gravitational contraction (such as tidal friction) to extend the age of the solar system, but none could reach the age required by Darwin. Similarly, some biologists worked to speed up evolutionary processes by positing separate events of abiogenesis to shave off some of the required time for diversification of various kingdoms. But these too could not rectify the problem.

Ultimately, the article throws its weight in the camp of the doomed astronomers. Interestingly, much of the same rhetoric in use by anti-evolutionists today can be found in the article. They state, “it is not surprising to find men of science, who not only have not the slightest doubt about the truth of their own pet theories, but are ready to lay down the law in the realms of philosophy and theology, in science which with, to judge from their immoderate assertions, their acquaintance is of the most remote? Such language is to be expected from the camp-followers in the army of science, who assurance is generally inversely proportional to their knowledge, for many of those in a word who affect to popularize the doctrine of Natural Selection.”

In time, Darwin would win the battle as astronomers would realize that gravitational contraction was just the match that lit the fuse of fusion. However, we must ask whether scientists would have been as quickly able to accept the proposition of stellar fusion had Darwin not pointed out the fundamental contradiction in ages?

13 Replies to “Darwin vs. the Sun”

  1. in 1859, Darwin published the Origin of Species in which he required an age of at least two billion years.

    I’m sorry, but that doesn’t pass the smell test. If no one had been discussing in terms of billions of years, how would Darwin, which had little evidence of the rate of evolution, assess such a number?

    Darwin made his own estimates on the order of hundreds of millions of years:

    “When Charles Darwin and Alfred Russel Wallace proposed their theory of evolution in 1858, they were following the geologists’ estimates. They felt that hundreds of millions of years – or maybe more – were needed to explain the origin of the species. The age of the Earth was so important to Darwin that he had made geological studies of his own. Included in the first edition of On The Origin of the Species
    by Natural Selection was an estimate of the time needed to wash away the Weald, a valley in southeast England formed of the eroded remains of a uplifted structure called an anticline. He estimated that that erosion alone would require 300 million years.

    Darwin himself was bowled over by Kelvin’s careful analysis. He could not escape the logic! He was so troubled that he removed any reference to time scales from later editions of Origin of the Species. The shy Darwin thought of Kelvin as a “odious spectre” [4].””

    I searched the online version of OOS.

    On the Weald:

    “I am tempted to give one other case, the well-known one of the denudation of the Weald. Though it must be admitted that the denudation of the Weald has been a mere trifle, in comparison with that which has removed masses of our palæozoic strata, in parts ten thousand feet in thickness, as shown in Prof. Ramsay’s masterly memoir on this subject. Yet it is an admirable lesson to stand on the North Downs and to look at the distant South Downs; for, remembering that at no great distance to the west the northern and southern escarpments meet and close, one can safely picture to


    oneself the great dome of rocks which must have covered up the Weald within so limited a period as since the latter part of the Chalk formation. The distance from the northern to the southern Downs is about 22 miles, and the thickness of the several formations is on an average about 1100 feet, as I am informed by Prof. Ramsay. But if, as some geologists suppose, a range of older rocks underlies the Weald, on the flanks of which the overlying sedimentary deposits might have accumulated in thinner masses than elsewhere, the above estimate would be erroneous; but this source of doubt probably would not greatly affect the estimate as applied to the western extremity of the district. If, then, we knew the rate at which the sea commonly wears away a line of cliff of any given height, we could measure the time requisite to have denuded the Weald. This, of course, cannot be done; but we may, in order to form some crude notion on the subject, assume that the sea would eat into cliffs 500 feet in height at the rate of one inch in a century. This will at first appear much too small an allowance; but it is the same as if we were to assume a cliff one yard in height to be eaten back along a whole line of coast at the rate of one yard in nearly every twenty-two years. I doubt whether any rock, even as soft as chalk, would yield at this rate excepting on the most exposed coasts; though no doubt the degradation of a lofty cliff would be more rapid from the breakage of the fallen fragments. On the other hand, I do not believe that any line of coast, ten or twenty miles in length, ever suffers degradation at the same time along its whole indented length; and we must remember that almost all strata contain harder layers or nodules, which from long resisting attrition form a breakwater at the base. Hence, under ordinary circumstances, I conclude that for a cliff 500 feet in height, a denudation


    of one inch per century for the whole length would be an ample allowance. At this rate, on the above data, the denudation of the Weald must have required 306,662,400 years; or say three hundred million years.

    The action of fresh water on the gently inclined Wealden district, when upraised, could hardly have been great, but it would somewhat reduce the above estimate. On the other hand, during oscillations of level, which we know this area has undergone, the surface may have existed for millions of years as land, and thus have escaped the action of the sea: when deeply submerged for perhaps equally long periods, it would, likewise, have escaped the action of the coast-waves. So that in all probability a far longer period than 300 million years has elapsed since the latter part of the Secondary period.

    I have made these few remarks because it is highly important for us to gain some notion, however imperfect, of the lapse of years. During each of these years, over the whole world, the land and the water has been peopled by hosts of living forms. What an infinite number of generations, which the mind cannot grasp, must have succeeded each other in the long roll of years! Now turn to our richest geological museums, and what a paltry display we behold!”

    On the rate of evolution:

    “On the sudden Appearance of Groups of allied Species in the lowest known Fossiliferous Strata.

    There is another and allied difficulty, which is much more serious. I allude to the manner in which many species in several of the main divisions of the animal kingdom suddenly appear in the lowest known fossiliferous rocks. Most of the arguments which have convinced me that all the existing species of the same group are descended from a single progenitor, apply with nearly equal force to the earliest known species. For instance, it cannot be doubted that all the Silurian trilobites are descended from some one crustacean, which must have lived long before the Silurian age, and which probably differed greatly from any known animal. Some of the most ancient Silurian animals, as the Nautilus, Lingula, &c., do not differ much from living species; and it cannot on our theory be supposed, that these old species were the progenitors of all the species

    [page] 379

    belonging to the same groups which have subsequently appeared, for they are not in any degree intermediate in character.

    Consequently, if the theory be true, it is indisputable that, before the lowest Silurian or Cambrian stratum was deposited long periods elapsed, as long as, or probably far longer than, the whole interval from the Cambrian age to the present day; and that during these vast periods the world swarmed with living creatures. Here we encounter a formidable objection; for it seems doubtful whether the earth in a fit state for the habitation of living creatures has lasted long enough. Sir W. Thompson concludes that the consolidation of the crust can hardly have occurred less than 20 or more than 400 million years ago, but probably not less than 98 or more than 200 million years. These very wide limits show how doubtful the data are; and other elements may have to be introduced into the problem. Mr. Croll estimates that about 60 million years have elapsed since the Cambrian period, but this, judging from the small amount of organic change since the commencement of the Glacial epoch, seems a very short time for the many and great mutations of life, which have certainly occurred since the Cambrian formation; and the previous 140 million years can hardly be considered as sufficient for the development of the varied forms of life which certainly existed towards the close of the Cambrian period.”

    [My bold.]

    So Darwin seems at the most be suspicious of Kelvin’s “hard limit”, since he a) derives longer geological times b) find inconsistencies with the observed rate of evolution (such as it was).

    I haven’t read this religious text on science, but I would never, ever trust the most famous and extensive quote mine and strawman fabricator (religions at large) in the world’s history! (O.o)

    1. You’re absolutely right. The 2 billion year estimate didn’t come from Darwin. It came from a contemporary of his, St. George Jackson Mivart. I misread the article which even cited that figure as such and accepted my misreading without further thought because I seemed to recall Darwin accepting and figures in the range of billions of years later, well after the publication of OOS.

      I’ll make the appropriate corrections.

      I should also note that I don’t trust such sources. This is one of many I’ve been looking at for a project of mine and numerous ones have laid out the same general story. I wrote this article because this one was one of the most comprehensive summaries, as well as including the interesting bit of anti-science I quoted at the end which was notable. I expounded more on that in my blog.

      1. Ah, thanks.

        Much as it annoys me, I would apologize to religion in general then. But St. George Jackson Mivart is in Wiki as biologist going catholic, so I can’t do that either, maybe he had ulterior motives at the time. (But scientifically speaking it wasn’t a bad guess.)

        So I’ll have to leave my blow up open, it is a fact notwithstanding the exemption here and there. I’ll have to apologize to this magazine specifically.

      2. And with “this” magazine I mean “that” magazine. 😀

        Btw, ironically it is my historical naiveté that prompted the discovery of the erroneous attribution (as it turned out), since I can’t remember Darwin having to accept even longer times. But certainly the excerpts I found indicates that you can derive such estimates by summing over estimates of individual geological and biological processes at the time Darwin and contemporaries began to puzzle the facts together without prejudice.

  2. Any soon now I expect the biggest number of forum posts ever in the history of UT because of this topic.

    1. Well, at least you got the biggest comment ever from me. I didn’t want to wait on the several links approval, so I QFT instead.

  3. The first sentence is wrong; You state; “Today, we take it for granted that the Sun produces energy via nuclear fusion.

    What we take for granted is that the stars undergo stellar evolution, and that knowing the the behaviours of stars throughout the universe, means we can piece together the origin and future of the universe. Better still we can predict the outcome of the Sun when it starts running out of fuel and cause the heat death on the Earth.

    Also nuclear fusion is an important process in which the stars are able to shine, but it is not the only significance. In a nutshell, fusion processes make the elements that enable life on Earth (or likely elsewhere). Darwin didn’t have that important connection, so he could answer the origins of living creatures or the biological systems they inherit. Had he had the information, he could have connected some of the uniqueness of biology (transport of organic matter and water in in cells, DNA reproduction on inherited traits, etc.)

    Therefore, IMO, claiming; “In time, Darwin would win the battle as astronomers would realize that gravitational contraction was just the match that lit the fuse of fusion.” isn’t really the central point. Evolution was not only time dependant, it was also based on energy production and element construction of life. (Sagan’s old star stuff.) Knowing and understanding stellar evolution was the key. It is this that set the clues to story of the origins and age of the Earth.

    Darwin was fifty or sixty years too early.

    1. What I see as the take-away message of this article is that the predictive power of Darwin’s theory was so strong that it even predicted that all of the eminent physicists and astronomers of his time were missing fundamental information about the production of energy in the sun. His theory did not have anything to say about how the elements came to exist, and that is not something I know of him discussing, so I don’t really see how that would be the central point. It’s something we can only see as a part of the puzzle in hindsight. How long the sun could produce energy for was part of the puzzle in Darwin’s time, and he did have something to say about it. Turns out he was on to something.

      I don’t see how the first sentence is wrong. Nor do I see how any of your points would do anything other than obfuscate the main point of the article. We do take it for granted that stars undergo fusion. That this fusion cycle is part of a larger process is beyond the point of this article. If we were to follow your logic further, we couldn’t write this article without explaining how the hydrogen was formed, and how we came to our inflationary theory of the early universe, and that if Darwin came a bit later, maybe he could have tied that in with his theory as well.

    2. And may I add, he was not 50 or 60 years too early, that he did what he did suggests he was right on time 🙂

  4. The accuracy debate aside, the interesting aspect of this article for me is the comparison of what we know now compared to what we thought we knew then. Two separate branches of science which today are even more separate both held pieces of the jigsaw that connected separately to the missing piece. I wonder how many truths today are similarly held – independently pointing towards a greater truth. I look forward to looking back and thinking, now why didn’t we see that?

    1. Now you make me feel bad at nitpicking accuracy again, but I would say that in your interesting observation IMHO it was at least 3 (!) branches converging – geology (sedimentation and layering, as exemplified by Darwin’s treatment in OOS above), biology (species relatedness, hybrids, island species, et cetera), with fossils somewhere in between perhaps, and physics.

      FWIW, stellar evolution/standard cosmology and nuclear physics/particle physics have undergone some of the same connection process. And I agree, it is really exciting when that happens!!!

  5. This is an early case of the weak anthropic principle (WAP). The WAP is a guiding rule that tells us that since life and our selves exist the universe must be structured in such as way as to make that possible. In other words since we exist the universe must be structured to let that occur. This is in contrast with the strong AP, which is a counter positive that says the universe can only occur if there is intelligent life within it. The existence of life and our species was shown by Darwin to require hundreds of millions of years, in contrast to Biblical ideas of a few thousand years, which required solar physics outside the then known principles.

    This is something which faces us today with issues of gauge hierarchy and so called fine tuning. The string landscape must be configured in such as way that our universe must exist with the particle masses and properties we observe. In our current age we are working with a similar problem which involves not just the physics of the sun, but the entire universe.

    Torbjorn Larsson OM is right about the time frames. Hutton in the early 19th century demonstrated geologically the Earth had existed on million year time frames. Hutton advanced uniformitarianism of sedementation and layering. This was a bit of a thunderbolt at the time, and came at a time of comparative conservative retrenchment of society and a resurgence of religion. Sounds a bit like our current age. Darwin extended time frames by about 1 to 2 orders of magnitude, and it was known by then there were fossils of previous life forms which had existed 10s of millions of years prior to our age. Darwin demonstrated a process for the relatedness of species of life which required 10s of millions of years to operate. By the late 19th century the duration of the Earth and life was a few hundred million years. That got extended an order of magnitude by the early 20th century and another order of magnitude with astronomy and cosmology by the mid 20th century.


  6. Didn’t Kelvin/Thomsen also debunk CDarwin’s evolution on the basis of his estimate of the age of the earth –something like estimating a rate of cooling and projecting backwards. I’m thinking he arrived at a time frame of 500,000 years. And wasn’t that figure tossed out when science began to teach nuclear activity at earth’s core, which would change a cooling rate? I wonder if geology or geophysics still works in that area: trying to give an estimate of the earth’s age and considering a cooling rate, energy from the sun added, and trying to guess what heat is added by (what?) amount of nuclear energy? Or maybe no one gives much attention to that, and considers other parameters (radio-isotope dating, etc) to be governing.

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