Ancient tree rings suggest sunspot cycles have been ongoing for 290 million years

Posted: January 20, 2017 by oldbrew in History, research, Solar physics
Tags: ,

Petrified log at Petrified Forest National Park, AZ [image credit: Jon Sullivan / Wikipedia]

Petrified log at Petrified Forest National Park, AZ
[image credit: Jon Sullivan / Wikipedia]

They seem to base their estimates of the past solar cycle length on a study of only 79 years’ worth of data which is almost certainly too short for high accuracy, but the results are interesting nevertheless.

A pair of German researchers has found evidence in ancient tree rings of a solar sunspot cycle millions of years ago similar to the one observed in more modern times, reports

In their paper published in the journal Geology, Ludwig Luthardt and Ronny Rößler describe how they gathered an assortment of petrified tree samples from a region in Germany and used them to count sunspot cycles.

Scientists know that the sun undergoes a sunspot cycle of approximately 11 years—some spots appear, grow cooler and then slowly move toward the equator and eventually disappear—the changes to the sun spots cause changes to the brightness level of the sun—as the level waxes and wanes, plants here on Earth respond, growing more or less in a given year—this can be seen in the width of tree rings.

In this new effort, the researchers gathered petrified tree samples from a region of Germany that was covered by lava during a volcanic eruption approximately 290 million years ago (during the Permian period), offering a historical record of sun activity.

The research pair obtained 43 petrified tree specimens (tree-trunk slices) and report that they were able to count 1,917 rings which were preserved well enough to allow for observation under a microscope.

Because the trees had all died at the same time, the researchers were able to establish a baseline between them which allowed for comparing tree ring growth between samples over the same time periods—which covered 79 years.

Doing so, they report, revealed very clearly a cycle of growth similar to that seen in modern trees, though in this case, it was slightly different. Today the cycle is an average of 11.2 years, back then it was 10.6—close enough, the researchers suggest, to conclude that the sun has been behaving very predictably for at least 290 million years.

It should be noted that not everyone agrees with the theory that sunspot activity leaves such a clear record in tree rings—other factors might be involved such as general global temperature, weather patterns or even outbreaks of insect populations.

Source: Ancient tree rings suggest sunspot cycles have been ongoing for 290 million years |

  1. This makes sense, I guess. I can’t remember where I read it, but I am pretty sure there is something of a consensus about the general source of the 11/22 year cycle – namely a property of magnetized plasma.

    The sun has ‘differential rotation’, ie does not rotate as a solid body. And of course the equator moves the fastest. Apparently this produces a Coriolis-type effect at the solar equator – except not liquid or gas, but plasma. .. The point being that magnetized plasma when stretched – because it is attracted to itself magnetically – apparently produces ‘torsional oscillations’, and the torsion just increases and increases, for around 11 years, then finally some magnetic field snaps, or something, and the polarity inverts. … this would also be why there are two solar sunspot maximums

    re: the magnetic fields that take about one cycle to go from the pole to the equator (the easiest to see) pretty sure this is thought to be a function of the equatorial torsional oscillations & not the other way around.

    all ASFAIK (I was not able to find a good link in about ten minutes of trying)

  2. rishrac says:

    Slightly off topic, the White House page for climate change is gone.

    [reply] must be the wind of change 😉

  3. hunter says:

    This is a fascinating use of paleo research to help establish just how important the cycles of our sun and moon are to life on – and the existence of- Earth.

  4. Sparks says:

    Assuming the suns polarity and polar field has continued to reverse over 290 million years (based on 79 years of data) How can there be Ice ages and cold periods? this sounds like the solar/earth climate is being portrayed as being remarkably stable for a reason.

    Just saying that it stands out!

  5. oldbrew says:

    Sparks: ice ages are more a case of what the Earth is doing, according to theory.

    But the theory is not watertight.

  6. kuhnkat says:

    This sounds like the petrified tree they are measuring is not 290 million years old…

  7. oldbrew says:

    kuhnkat – there were 43 petrified trees in the study, which were all killed at the same time by volcanic lava flows.

  8. Sparks says:

    Oldbrew, I understand Milankovitch cycles and changes in planetary orbits, the correlation between planetary climate is well known, but I’ve been pointing out for years that there is something else going on, there is also a correlation between planetary orbits and the suns polarity/polar field reversal

    What do you think will happen when the suns polarity/polar field stops reversing?

    Because the suns polarity/polar field reversal is linked to the expansion and contraction of planetary orbits, it’s only a matter of time before the solar system balances out (so to speak) and the suns polarity/polar field no longer reverses.

    This is what I believe is a primary cause of ice ages,

    In the records of our recent past alone there is evidence that the sun has had a major impact on climate and brought about “mini ice ages” this is with only a few years of the suns polarity/polar field not reversing.

    Hank, the ‘differential rotation’ does exist and does cause residual sunspot activity, we know this and I believe that the amount of activity caused by the suns differential rotation can be extrapolated by how much residual sunspot activity occur during periods when the suns polarity/polar fields did not reverse for a known period of time, for example during the maunder minimum, this obviously shows a small ongoing effect caused by ‘differential rotation’ but the increase in solar activity/sunspots etc, is a result of the polarity/polar fields reversing.

    The solar system as a whole interacts on very basic understood principles.

    The ‘solar dynamo’ is not constructed correctly by solar physicists, the ‘differential rotation’ has a weak effect on the sun, and the effect itself is a residual part of the solar polarity/polar fields reversing.

    All the best guys, it’s always interesting here 🙂

  9. Sparks says:

    This is a graph showing changes in Jupiter’s orbit over time, it is similar to “Milankovitch cycles”.

    It’s kinda deceptive because there’s much more going on, but hopefully you’ll understand the point of it.

  10. oldbrew says:

    The Sun and its solar system are in a spinning spiral arm of the Milky Way’s galactic disk, so external forces can also apply.

  11. jim says:

    I follow what your saying, and here comes my periodic “but” or “and”. A star is a gravity well. It’s also a huge consumer. Energy is transformed from the stars mass consumed. What does the star consume. Feast or famine, it consumes it’s environment. Dust and whatever. OK in the old days it was called aether. Now a days it’s called cosmic ” junk”, but it’s just one of the variables not counted in the “warming” equation. It’s kind of like “torque” leaves out the baricenter and positioning of the gas giants, and the minors. As if they had no or little effect on the outputs and mixings, but still an interesting read.

  12. oldbrew says:

    Geomagnetic activity vs. sunspot data [2005]

    ‘We show that the index commonly used for quantifying long-term changes
    in solar activity, the sunspot number, accounts for only one part of solar activity and using
    this index leads to the underestimation of the role of solar activity in the global warming
    in the recent decades. A more suitable index is the geomagnetic activity which reflects all
    solar activity, and it is highly correlated to global temperature variations in the whole period
    for which we have data’

  13. Sparks says:

    Getting back to tree rings,

    Shouldn’t a forest from the distant past have the same factors affecting the growth of rings as forests today? all things being equal in this respect, other factors such as weather patterns, mineral availability and outbreaks of insects, fungi and other parasites should have a similar pattern when it comes to tree rings.

    Did you know certain types of trees die when there are fungi outbreaks? some fungi that are harmful to trees thrive in damp cold conditions in a forest, there was an outbreak here in a forest locally during the last solar minimum, ongoing from 2008-2010, very cold prolonged winters were recorded over this period and it destroyed a lot of acres, obviously not a lot of tree ring growth going on.

    There’s not a lot of insect outbreaks in this part of the world that can wipe out forests, (if any), but in times of healthy tree ring growth, these periods are warm and insect populations are healthy and thriving, I haven’t seen any evidence that they reduce the growth of trees.

    If examining tree rings, going by the lack of growth there’s a high certainty that cold periods were occurring, if you have enough samples, but this paper seems to do the opposite by finding 79 years of healthy tree ring growth and imposing assumptions on their samples that there is a period of 290 million years of healthy tree ring growth

    Regular solar cycles or even climate, over a period of 290 million years is laughable, it’s borderline criminal or unbelievably ignorant to suggest it…

  14. Sparks says:

    *stable climate

  15. oldmanK says:

    Some background reading on tree-rings. Note that the abrupt changes appear much too fast to connect to planetary movement.

  16. Sparks says:

    “The Sun and its solar system are in a spinning spiral arm of the Milky Way’s galactic disk, so external forces can also apply.”

    Different scale, our solar system doesn’t interact on a the time scale that galaxies do, on a galactic scale matter is repulsive and gravity is attractive.

    Let me explain some thoughts, Throughout the entire universe, imbalances occur, we call it pressure differences here on Earth, in space and time, these imbalances cause weak currents (on a relative scale) this in turn produces intense gravitational eddies, just like whirlpools forming on a deep calm pool. These gravitation eddies which can be described as black holes form in space and time, this is a continuous and infinite process on any scale, once eddies/black holes are formed, they begin to interact with each other, massive black holes in space and time attract each-other and when this occurs the reaction between ‘black holes’ breakdown and produce Galaxies,

    The formation of galaxies/quasars throughout the universe on our timescale makes it appear that an enormous explosion occurred, We are really observing an on going process from a small perspective in time and space.

    We view the universe as if a big bang happened in X point in time, almost like we’re observing an explosion in slow motion, This also gives us the appearance that the universe is expanding.

    Our solar system being in a spinning spiral arm of our galaxy has no relative effect on an intelligible time scale that we can compare to earths climate.

  17. oldbrew says:

    Fossilised tree and ice cores help date huge volcanic eruption 1,000 years ago to within three months
    January 24, 2017

    ‘An international team of researchers has managed to pinpoint, to within three months, a medieval volcanic eruption in east Asia the precise date of which has puzzled historians for decades. They have also shown that the so-called “Millennium eruption” of Changbaishan volcano, one of the largest in history, cannot have brought about the downfall of an important 10th century kingdom, as was previously thought.

    Writing in the journal Quaternary Science Reviews the team describes how new analysis of the partly fossilised remains of a tree killed by the eruption, and ice cores drilled in Greenland, lead them to conclude the eruption occurred in the final months of 946 AD.’

    Read more at:
    – – –
    Re: ‘the final months of 946 AD’
    Earth would have had conjunctions with all four giant planets between June and August that year, according to Arnholm’s solar simulator. This graphic shows the fourth one with Neptune.

  18. ulric lyons says:

    If a given 79 year study period does not include a solar minimum, then the average sunspot cycle length in that period could easily be as little as 10.2 to 10.4 years.

    [reply] indeed

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