The testimony of trees about one of the most violent solar storms

Large solar storms are very unusual. There are not even ten known as a result of the traces they left on Earth in the last 14,500 years. A new study provides revealing data about one of them.

If a solar storm similar to these were to occur today, it would be catastrophic for modern technological society, cutting off communications in countless places, rendering communications satellites useless and causing massive electrical blackouts that could last for weeks.

The team of Irina Panyushkina and Timothy Jull, both from the University of Arizona in the United States, has now found evidence of the specific year in which one of these colossal solar storms was triggered.

By analyzing annual growth rings in tree trunks for the presence of carbon-14, a naturally occurring radioactive variant of carbon, the team discovered a peak dating back to 664 BC or 663 BC. That peak reveals when the only solar storm occurred. extremes of the last 14,500 years of which the exact time was still unknown.

Carbon-14 is continually formed in the atmosphere as a result of cosmic radiation. A few months later, carbon-14 completes its journey from the stratosphere to the lower atmosphere, where it is absorbed by trees and becomes part of the wood as they grow.

Determining the exact timing of a massive solar flare provides important data for scientists studying the Sun’s activity over time.

The trunk of an ancient tree lies exposed on the muddy bank of a Siberian river. Samples taken from these long-living trees allowed researchers to search for radiocarbon spikes documenting extreme solar storms in the distant past. (Photo: Irina Panyushkina, University of Arizona)

Until 2012, there was no evidence of the existence of the class of extreme solar storms today called Miyake events. That year, the Japanese physicist Fusa Miyake presented the revealing results of a study on one of those extreme solar storms, the one that occurred in the year 775 AD. For that study, the analyzes of radioactive carbon isotopes in the annual growth rings of the trees were decisive.

The largest solar storm directly observed and documented by humans of the time occurred in 1859 and is known as the Carrington Event. It caused enormous disruption on Earth: it destroyed telegraph systems and created a nighttime aurora so bright that birds began to sing, believing that the Sun was already rising. However, storms classified as Miyake Events are on the order of ten times more powerful than the Carrington Event.

Miyake events occur when the sun’s electromagnetic field weakens, allowing plasma from the sun’s surface to escape into space. With increasing solar activity, protons bombard the Earth’s atmosphere and trigger reactions that cause a spike in radioactive isotopes.

“Thanks to radiocarbon from tree rings, we now know for sure that six Miyake events have occurred in the last 14,500 years,” says Panyushkina.

The study is titled “The timing of the ca-660 BCE Miyake solar-proton event constrained to between 664 and 663 BCE.” And it has been published in the academic journal Communications Earth & Environment. (Fountain: NCYT by Amazings)