Destructive Solar Storms May Not be Responsible for Radiation Shadows on Earth Trees

An enigmatic biochemical signature with unknown origins stored for ages from the inside of the trunks of Earth's trees has recently become even more enigmatic. Scientists have uncovered remnants on Earth of six severe bursts of radiation described as Miyake events during the previous 9,300 years in the last decade.

The most widely accepted theory is that these strange signals were left behind by gigantic solar storms, prompting several scientists to predict that the upcoming Miyake event might halt the world's electrical infrastructure. However, a recent study published in the Journal of the Royal Society A in October reveals that the perplexing radiation may be caused by more than simply solar flares.

A Miyake Event is something horrible that comes from the Sun to Earth, and we know how frequently they happen since they leave an impression in tree rings. Because it is feasible to count the rings on a tree to determine its age, it is also possible to witness historical cosmic events that date back thousands of years.

What is a Miyake Event?

It can occur when tree rings indicate a level of an isotope named carbon-14 that is approximately 20 times greater than normal. Massive outbursts of cosmic rays occur once every thousand years, but the reasons are unknown and the impact on the world's infrastructure would be unprecedented, according to Dr. Benjamin Pope of the University of Queensland's School of Mathematics and Physics, in a report from Forbes.

Pope headed a team that created software to analyze every bit of data available on the bands of millennia-old trees. When radiation affects the environment, radioactive carbon-14 is produced that permeates through all the air, oceans, and plants, including animals, producing a yearly record of radiation in tree rings, according to first researcher Qingyuan Zhang, an undergraduate mathematics student who built the program.

They then used a global carbon cycle model to reproduce the activity over 10,000 years to determine the extent and nature of these "Miyake Events." Solar flares, which unleashed a burst of energetic particles into space, were suspected of causing such catastrophes.

Earlier Developing Studies on Miyake

Physicist Fusa Miyake of Nagoya University in Japan had been investigating Japanese cedar tree rings in 2012 when she discovered a dramatic rise in radiocarbon - a variation of carbon that may develop when cosmic radiation impacts Earth's atmosphere - in rings going back to around A.D. 774. Since then, five additional identical bursts, now known as Miyake events, have just been discovered in tree rings and polar ice cores worldwide, following the published study in Nature. Because of the spikes' worldwide prevalence, many experts believe they are of alien origin. The most widely accepted hypothesis is that huge solar outbursts, or flares, bombarded Earth with massive blasts of radiation.

The 1859 Carrington incident damaged telegraph wires and ignited an electrical fire in Pittsburgh; it was the most violent solar flare in recorded history. Pope remarked that the radiation levels connected with Miyake events are more than 80 times higher than those associated with Carrington events. They might endanger world technology.

But there are flaws in the solar storm scenario. Some scholars believe that the radiation levels from the 774 incident were too great to be caused by a single solar flare. Furthermore, ice cores, which may potentially contain chemical residues of solar storms, have not yet provided evidence of higher solar intensity per Miyake event.

Performing Developing Hypothesis

As a result, Pope and his colleagues tested the leading theory. They used computer simulations of Earth's carbon cycle to assess all publicly accessible tree ring data from the six Miyake incidents. The team was able to compute the length, timing, and intensity of each event as a result.

If the Miyake episodes are related to sunspot activity, they may coincide with solar maximum, which occurs every 11 years whenever solar flares become much more common. However, the researchers discovered no link between Miyake incidents and any stage of the sunspot cycle. Furthermore, the researchers found that two of the occurrences appeared to endure more than a year - an unusually long duration for solar flares, which usually span hours or days.

If solar flares caused the events, trees at the poles, where Earth's defensive magnetic field is thinner, should have higher amounts of Miyake event radioactivity. However, the researchers discovered no such pattern.

As Global Insider reports, Pope mentioned that the data did not go completely out of the solar storm idea. He believes inadequate tree ring data may conceal a relationship between solar activity and Miyake incidents. New Antarctic ice-core data, which is being evaluated by Australian Nuclear Science and Technology Organization experts and will presumably be published next year, may give additional answers.

Nuances in the Earth's carbon cycle that the models did not capture might impact the conclusions. For example, depending on the species, plants may metabolize radiocarbon at varying rates. However, the mystery remains unresolved; Pope isn't worried about another Miyake incident occurring very soon. He believes there is a 1% possibility of one occurring during the next decade.

Check out more news and information on Sun in Science Times.