Tree Rings Offer Insight Into Past Devastating Radiation Storms
www.uq.edu.au . October 26, 2022
What is a Miyake Event? – its more like a cosmic explosion that may last weeks, months, or even years. They have demonstrated in the UQ study that they are not associated with solar flares. They are huge bursts of cosmic radiation, and have occurred approximately once every thousand years but what causes them is not yet clear. The 993-994 CE spike was a rapid increase in carbon-14 content from tree rings, and followed the 774-775 CE carbon-14 spike.
What happened in 774 CE? In the year 774 an enormously powerful blast of matter and energy from space slammed into Earth. The worst recorded solar storm in history was the 1859 solar storm, better known as the Carrington Event. It was powerful enough to cause sparks and fires in telegraph machines and caused power grid failures. The 774 event was so powerful that the storm started multiple forest fires. A study published in Nature journal where a group of Japanese researchers analysed tree ring data to find out about the existence of this ‘solar storm’. According to it, this particular event took place between 774-775 CE. It is estimated that its intensity was 10 times higher than the Carrington event. The evidence was found in Cedar trees in Japan which all show a huge spike in carbon-14.
THE UQ STUDY
A University of Queensland study has shed new light on a mysterious, unpredictable and potentially devastating kind of astrophysical event. A team led by Dr Benjamin Pope from UQ’s School of Mathematics and Physics applied cutting edge statistics to data from millennia-old trees, to find out more about radiation ‘storms’. The UQ researchers analysed data from tree rings to measure historical cosmic events.
“These huge bursts of cosmic radiation, known as Miyake Events, have occurred approximately once every thousand years but what causes them is unclear,” Dr Pope said. “The leading theory is that they are huge solar flares. “We need to know more, because if one of these happened today, it would destroy technology including satellites, internet cables, long-distance power lines and transformers. “The effect on global infrastructure would be unimaginable.”
Enter the humble tree ring. First author UQ undergraduate maths student Qingyuan Zhang developed software to analyse every available piece of data on tree rings.“Because you can count a tree’s rings to identify its age, you can also observe historical cosmic events going back thousands of years,” Mr Zhang said. “When radiation strikes the atmosphere it produces radioactive carbon-14, which filters through the air, oceans, plants, and animals, and produces an annual record of radiation in tree rings. “We modelled the global carbon cycle to reconstruct the process over a 10,000 year period, to gain insight into the scale and nature of the Miyake Events.”
The common theory until now has been that Miyake Events are giant solar flares. “But our results challenge this,” Mr Zhang said. “We’ve shown they’re not correlated with sunspot activity, and some actually last one or two years. “Rather than a single instantaneous explosion or flare, what we may be looking at is a kind of astrophysical ‘storm’ or outburst.” Dr Pope said the fact scientists don’t know exactly what Miyake Events are, or how to predict their occurrence is very disturbing. “Based on available data, there’s roughly a one per cent chance of seeing another one within the next decade. “But we don’t know how to predict it or what harms it may cause. “These odds are quite alarming, and lay the foundation for further research.”
The research is published in Proceedings of the Royal Society A. The study was also completed with undergraduate maths and physics students Utkarsh Sharma and Jordan Dennis. The work was supported by a philanthropic donation to UQ from the Big Questions Institute.
CONTACT: Dr Benjamin Pope, [email protected], +61 (0)439 730 708; Faculty of Science Media, [email protected], +61 (0)438 162 687
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COMMENT
So, according to the Queensland research, the chance that a Miyake Event hitting the Earth is approximately “a one per cent chance of seeing another one within the next decade”, or roughly 1 in every 1000 years. So, why worry considering that the last possibly similar cosmic event was in 1859. However, the researchers warn “But we don’t know how to predict it or what harms it may cause. “These odds are quite alarming, and lay the foundation for further research.”
Now if we compare these odds to another possible nasty cosmic event, such as the chance of an extinction level asteroid impacting the Earth with a 1 km diameter rock, it is estimated that the odds are once in every 500,000 years on average. Large collisions – with 5 km (3 mi) objects – happen approximately once every twenty million years. However, despite these long odds, and that, according to NASA, there are no known [sizable] asteroids on a collision course with Earth for the foreseeable future. $ millions are being spent now to find ways to deflect such an object if it was ever observed heading our way. For example, NASA’s, recent DART Mission cost $324.5 million (US dollars) See: https://en.wikipedia.org/wiki/Asteroid_impact_avoidance
So, if NASA considers odds of 1 in every 500,000 years worth spending that sort of money on, what about addressing the much better odds ratio of a Miyake Event happening every 1000 years – or sooner?