NC West Virginia News

Severe space weather events can leave evidence in tree rings, according to a researcher from West Virginia University. Amy Hessl, a geography professor at WVU's Eberly College of Arts and Sciences, suggests that this evidence could help prepare for future incidents that might disrupt communications satellites and pose risks to astronauts.

Hessl explains that ancient tree rings have revealed rare and extreme space weather events from the past. "If one of these events were to happen today and you were on a high latitude flight flying to Norway, you’d probably receive your lifetime dose of radiation on the plane," she said. "And if you were in space, it potentially could kill you."

Hessl has received over $202,000 in funding from the National Science Foundation to further investigate this topic. She notes that solar energetic particles can create radiocarbon through atmospheric reactions. Trees use carbon from the air to grow, so their annual rings document historical solar activity. These records have uncovered severe storms known as "Miyake events," characterized by sudden increases in atmospheric radiocarbon levels.

"Some of these events were really extreme and would be incredibly disruptive to our telecommunications system now," Hessl noted. The research community has identified nine Miyake events over the last 14,000 years.

Solar flares are typically responsible for these energetic particle events on Earth; however, particles may also originate from galactic cosmic rays initiated by supernovas. While most evidence indicates the sun as the source of Miyake events, Hessl hopes global tree ring records will help pinpoint causes and assess severity.

Hessl highlights potential biases in how trees absorb radiocarbon: "Until recently, scientists have assumed that trees take up radiocarbon evenly." She is studying why different species or locations show variations in radiocarbon uptake.

Collaborating with Maria Carbone from Northern Arizona University and Rachael Filwett from Montana State University, Hessl is examining three U.S. sites where wood dates back to major Miyake events. They aim to understand how different tree species record atmospheric changes consistently over time.

"We’re looking at three species that have very different physiological strategies for wood production," Hessl explained. The team compares bristlecone pines from Utah with bald cypress trees in North Carolina and oak trees preserved in Missouri riverbeds.

The study involves taking core samples or cross-sections of dead trees and dating each ring using cross-dating techniques. This approach allows them to determine if any living during Miyake events recorded those occurrences accurately.

"We’re trying to define how extreme those events were," Hessl stated. By analyzing how various trees record past occurrences and current radiocarbon uptake patterns, she aims to enhance preparedness for future threats like intense space weather affecting technological infrastructure.

Though such an event is considered unlikely due to its extremity, advanced preparation remains crucial according to Hessl's research findings.