Analysis of tree rings reveals highly abnormal solar activity in the mid-holocene

February 7, 2017
Picture of the bristlecone pine forest in California, the United States where the bristlecone pine sample for this study used to live (taken by Prof. A.J.T. Jull). In this forest, there are many living old trees exceed 1000 years old. Harsh environments make bristlecone pines very dense and long lives. Credit: Nagoya University

By analyzing the level of a carbon isotope in tree rings from a specimen of an ancient bristlecone pine, a team led by Nagoya University researchers has revealed that the sun exhibited a unique pattern of activity in 5480 BC. By comparing this event with other similar but more recent phenomena, they reported that this event may have involved a change in the sun's magnetic activity, or a number of successive solar burst emissions.

An international team led by researchers at Nagoya University, along with US and Swiss colleagues, has identified a new type of solar event and dated it to the year 5480 BC; they did this by measuring carbon-14 levels in tree rings, which reflect the effects of cosmic radiation on the atmosphere at the time. They have also proposed causes of this event, thereby extending knowledge of how the sun behaves.

When the activity of the sun changes, it has direct effects on the earth. For example, when the sun is relatively inactive, the amount of a type of carbon called carbon-14 increases in the earth's atmosphere. Because carbon in the air is absorbed by trees, carbon-14 levels in actually reflect and unusual solar events in the past. The team took advantage of such a phenomenon by analyzing a specimen from a bristlecone pine tree, a species that can live for thousands of years, to look back deep into the history of the sun.

"We measured the 14C levels in the pine sample at three different laboratories in Japan, the US, and Switzerland, to ensure the reliability of our results," A. J. Timothy Jull of the University of Arizona says. "We found a change in 14C that was more abrupt than any found previously, except for cosmic ray events in AD 775 and AD 994, and our use of annual data rather than data for each decade allowed us to pinpoint exactly when this occurred."

The team attempted to develop an explanation for the anomalous solar activity data by comparing the features of the 14C change with those of other solar events known to have occurred over the last couple of millennia.

"Although this newly discovered event is more dramatic than others found to date, comparisons of the 14C data among them can help us to work out what happened to the sun at this time," Fusa Miyake of Nagoya University says. She adds, "We think that a change in the of the sun along with a series of strong solar bursts, or a very weak sun, may have caused the unusual tree ring data."

Although the poor understanding of the mechanisms behind unusual solar activity has hampered efforts to definitively explain the team's findings, they hope that additional studies, such as telescopic findings of flares given off by other sun-like stars, could lead to an accurate explanation.

Explore further: Tree-rings reveal secret clocks that could reset key dates across the ancient world

More information: Fusa Miyake et al. LargeC excursion in 5480 BC indicates an abnormal sun in the mid-Holocene, Proceedings of the National Academy of Sciences (2017). DOI: 10.1073/pnas.1613144114

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RealityCheck
1 / 5 (3) Feb 15, 2017
From the above article:
For example, when the sun is relatively inactive, the amount of a type of carbon called carbon-14 increases in the earth's atmosphere.
How can that be? If the sun's wind/flare/ejections etc decreases, shouldn't the rate of C14 production in Earth's atmosphere also decrease?

Anyway, maybe the sun's activity was still as usual in that period BUT widespread/super volcanism injection of particulate/chemical 'blanket' into the troposphere/stratosphere blocked the solar particles/radiation and so reduced the sun's effects which would otherwise have produced as much C14 as usual?

More study/lateral thinking required into methodology/assumptions/factors etc before naively applying/concluding from such 'models', no matter how long such 'models' and assumptions have been around?
Uncle Ira
4 / 5 (4) Feb 15, 2017
@ Really-Skippy. How you are Cher? I am good me, just fine and dandy, thanks for asking.

How can that be? If the sun's wind/flare/ejections etc decreases, shouldn't the rate of C14 production in Earth's atmosphere also decrease?


No Cher they are correct. The "sun's wind/flare/ejections etc" causes the C14 to decay easier. When there is less of the "sun's wind/flare/ejection etc" the C14 is more stable, eh? So more of it.

Maybe what you are thinking of is the "cosmic rays" that make the C14 from nitrogen in the troposphere. They are different from the "sun's wind/flare/ejection etc". Less of them makes less of the C14.

How you like me now Cher?
RealityCheck
2 / 5 (4) Feb 16, 2017
Hi Ira. :)

Thanks for your polite on-topic reply. Yes, I initially thought that too; but then I recalled recent discoveries re solar-earth magnetic fields system/interactions behaving like 'particle accelerators' and producing high-energy particle-atmosphere impacts which mimic 'cosmic rays' coming from outside the sun-earth system. But anyway, even if what you have suggested is true, it still leaves the possibility that the measured 'events' related to periods of high vulcanism dust/chemicals in atmosphere which blocked solar effects, thus also resulting in increased buildup of C14? That is the possibility I am most interested in eliminating from the 'interpretive' conclusions in the study.

PS:
How you like me now Cher?
Personal 'likes' have (or should have) nothing to do with scientific research/discourse. Having said that, your above polite on-topic contribution to same is much appreciated. Now all that remains is for you to 'lose' that bot-voting program, hey! :)
Uncle Ira
4 / 5 (4) Feb 16, 2017
@ Really-Skippy. How you are again today Cher? I am still good, thanks for asking.

The "sun's wind/flare/ejections etc" going up causing the C14 going down and vis-a-verse I learn about when I was studying for Amateur Extra Class and my GROL. On the sections about transmission and propagation. During the solar max (that's when the sun is most active in it's 11 year cycle) is when radio transmission and reception is really good on the HF bands. The reason is there is less noise in the ionosphere because of the lower amount of C14 (and other noisy isotopes too).

Oh yeah, I almost forget. Sorry about the bot-voting program but I got to leave it on. At least until I buy a new computer, and that won't be anytime soon because it is already the top of the line super duper CIA grade model and should be for awhile. At least I am not doing the puppet army thing like you are. That is cheating Cher. One vote per couyon is the rule.
Uncle Ira
4 / 5 (4) Feb 16, 2017
P.S. for you Really-Skippy.

I almost forget another thing. The "sun's wind/flare/ejections etc" also makes the ionosphere more "thicker" with ions by striping away electrons from the molecules up there. That is also good for HF skip.
RealityCheck
2 / 5 (4) Feb 16, 2017
Hi Ira. :)

Yes, it's a complex relation, as I said. When you say more activity means less C14, I did point out that more C14 would be produced by more active solar-earth magnetic field system/interactions 'accelerating' particles to cosmic-ray energies. So naive assumptions from the time you were first told these things may not hold anymore since recent discoveries of solar-earth 'particle accelerator' processes.

The thickness of ionosphere itself varies/acts as already understood. No argument there.

Did you consider high vulcanism ejecta into atmosphere blocking solar effect thus affecting rate of C14 formation?

PS: You KNOW those sockpuppets now playing YOUR bot-voting game have nothing to do with me, mate. Don't just 'believe' things'; actually know, via evidence, not personal bias.

PPS: So, still shy of asking your 'mates' how to remove that bot-voting program? And your "top of the line super duper CIA grade model" computer 'allows' bot-voting programs?

Cheers. :)
gkam
1 / 5 (4) Feb 19, 2017
Bot-voting is just hate-voting and a sign somebody has no response to comments but vandalism.

Cheers, . . .
TheGhostofOtto1923
1 / 5 (1) Feb 20, 2017
Bot-voting is just hate-voting and a sign somebody has no response to comments but vandalism.

Cheers, . . .
But sometimes its the only attention you can get so sometimes its a good thing, right?

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