What happened to the sun over 7,000 years ago? 

Posted: February 10, 2017 by oldbrew in research, Solar physics, solar system dynamics

Solar activity [image credit: NASA]

Solar activity [image credit: NASA]

A tough question on the face of it, but the researchers claim to have unearthed a ‘new type of solar event’ based on evidence from one tree (according to this report).
H/T oldmanK

Nagoya, Japan – 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, as Scienmag reports.

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 tree rings actually reflect solar activity 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 magnetic activity 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.

Source: What happened to the sun over 7,000 years ago? | Scienmag: Latest Science and Health News

  1. oldbrew says:

    This writer says: This paper’s title should set off alarms for radiocarbon dating

    Also: Their last sentence sounds a warning: “In any case, the 14C variation of the 5480 BC event indicates an unprecedented anomaly in solar activity compared to other periods.”


  2. Stephen Richards says:

    We think that a change in the magnetic activity of the sun along with a series of strong solar bursts, or a very weak sun, may have caused the unusual tree ring data.”

    So an active or inactive sun or a sun that was inactive with large bursts of activity.

  3. oldmanK says:

    Further to my comments on ‘suggestion 25’ the paper does not explain much, though oldbrew’s link is helpful.

    Intcal13 here: http://www.radiocarbon.org/IntCal13%20files/intcal13.pdf may give some idea of the C14 changes obtained from comparing with tree ring data. The dates I have been after, viz 2345bce, 3195, 3500, 4375. 5200, the missing 5480, and 6200 all appear as jerks in the traces. But interpretation of the C14 anomaly – for me definitely- is still a big question.

    ps. bce (before common era) is ‘politically’ correct, and BP is awkward.

  4. E.M.Smith says:


    I just pronounce bce as “Before the Christian Era” and all that awkward PCness just evaporates…


  5. oldmanK says:

    @ E.M.Smith:

    I would prefer a datum tied to a reliable date, scientifically.

    I don’t want to rake any fires but the following I recently found, not so much as a surprise, but as a confirmation (and I leave it at that). Quote from book [[ We might ponder the words of St Augustine “What is now called the Christian religion, has existed among the ancients, and was not absent from the beginning of the human race, until Christ came in the flesh: from which time the true religion, which existed already, began to be called Christian”. August retr i 13. Quoted in F M Muller ‘Selected essays on Languages, Mythology and Religion, 1181, i 5.]]

  6. oldmanK says:

    Correction: date 1881 not 1181.

  7. In lumina says:

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