A groundbreaking research project led by Amy Hessl, professor of geography at West Virginia University’s Eberly College of Arts and Sciences, is investigating how tree rings can reveal devastating space weather events from Earth’s past.
Understanding Miyake Events
Ancient tree rings have uncovered evidence of rare and extreme space weather events known as “Miyake events,” characterized by sudden spikes in atmospheric radiocarbon levels. The first such events were identified in 774 AD and 993 AD, with seven more discovered over the past 14,000 years.
These events pose significant risks to modern technology and human safety. A similar occurrence today could deliver a lifetime dose of radiation to passengers on high-latitude flights and potentially prove fatal to astronauts in space.
The Science Behind Tree Ring Records
Carbon Recording Process
Solar energetic particles create radiocarbon through atmospheric reactions, which trees incorporate into their annual rings during wood formation. This process creates a natural historical record of solar activity.
Sources of Particle Events
While solar flares trigger most energetic particle events affecting Earth, galactic cosmic rays from phenomena like supernovas can also contribute. Current evidence suggests the sun as the primary source of Miyake events.
Research Challenges
Tree Recording Variability
Recent findings suggest that trees may not record radiocarbon uniformly, contrary to previous assumptions. Different species and locations show varying patterns of radiocarbon uptake, potentially affecting the reliability of these natural records.
Current Research Focus
Hessl’s team, supported by over $202,000 in National Science Foundation funding, is studying three distinct tree species:
- Bristlecone pine from Utah (evergreen conifer)
- Bald cypress in North Carolina (deciduous)
- Oak trees in Missouri riverbeds
Implications for Modern Society
The potential impact of a Miyake event on contemporary society would be severe, potentially disabling telecommunications systems with a recovery period of up to 15 years. This research aims to better understand these events’ characteristics, timing, and atmospheric effects to help prepare modern technological infrastructure for potential future occurrences.
Research Methodology
The team employs cross-dating techniques on pencil-sized core samples or cross-sections to precisely date tree rings. This analysis helps determine how different species record Miyake events in their ring chemistry.
While such extreme space weather events remain rare, this research emphasizes the importance of advanced preparation and understanding to protect modern technology and infrastructure from potential devastating impacts.
