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Carrington Event: Massive solar storm left scars in tree rings on Earth

In a remarkable scientific breakthrough, researchers have discovered a new way to study the impact of solar storms on Earth by analyzing the radiocarbon concentration in tree rings.

This finding has significant implications for understanding the frequency and severity of solar storms, as well as their potential effects on modern technology and society.

The study was conducted by a research group coordinated by the University of Helsinki, in collaboration with the Natural Resources Institute Finland (Luke) and the University of Oulu.

The team was able to detect a spike in radiocarbon concentration in trees from Lapland, Finland, following the Carrington Event of 1859, one of the largest recorded solar storms in the last two centuries.

Understanding solar storms and their impact

Solar storms occur when magnetized clouds of charged particles, known as solar plasma flows, are released from the Sun and interact with Earth’s geomagnetic field.

These interactions can result in geomagnetic storms, which can cause aurorae, disrupt electrical and mobile networks, and pose challenges for satellite and navigation systems.

“Radiocarbon is like a cosmic marker describing phenomena associated with Earth, the solar system and outer space,” says Markku Oinonen, Director of the University of Helsinki’s Laboratory of Chronology, who headed the study.

Decoding solar storm secrets in tree rings

To uncover the information stored in tree rings, researchers extract samples by carving from the wood material grown over individual years.

The samples are then processed to cellulose and converted into pure carbon through burning and chemical reduction. Finally, the fraction of radiocarbon in the pure carbon is measured using a particle accelerator.

“It’s possible that the excess of radiocarbon caused by the solar flare was primarily transported to the lower atmosphere through northern regions, contrary to the general understanding of its movement,” muses Doctoral Researcher Joonas Uusitalo from the Laboratory of Chronology.

Implications for modern society

A solar storm of the magnitude of the Carrington Event occurring in modern times would have severe consequences for our technology-dependent society.

It could disrupt electrical and mobile networks, cause major problems for satellite and navigation systems, and lead to issues in various sectors, such as air traffic. Therefore, accurate knowledge of solar behavior is crucial for societal preparedness.

“It’s also possible that the cyclic change in the production of radiocarbon in the upper atmosphere caused by the variation in solar activity has resulted in the local differences on the ground level seen in our findings,” Uusitalo adds.

Role of atmospheric dynamics and the carbon cycle

The study also addresses the atmospheric dynamics and the carbon cycle from the time before human-generated fossil fuel emissions.

The findings can help develop increasingly detailed carbon cycle models, contributing to a better understanding of our planet’s complex systems.

“The dynamic atmospheric carbon transport model was specifically developed for describing geographical differences in the distribution of radiocarbon in the atmosphere,” says Postdoctoral Researcher Kseniia Golubenko from the University of Oulu.

Solar storms, tree rings, and future research

While this fascinating study has opened up new avenues for investigating large solar storms like the Carrington Event, further research is needed to fully understand the implications of these findings.

Historical records show that significant geomagnetic storms also took place in 1730 and 1770, making them likely targets for future research.

As scientists continue to unravel the secrets hidden within tree rings, we can expect to gain a deeper understanding of the complex interactions between the Sun, Earth, and the cosmic forces that shape our world.

More about solar storms and the Carrington Event

As discussed above, solar storms, also known as solar flares or coronal mass ejections (CMEs), are explosive events that occur on the Sun’s surface.

These powerful eruptions release vast amounts of energy, radiation, and charged particles into space, potentially affecting Earth and other planets in the solar system.

Anatomy of a solar storm

Solar storms originate from sunspots, which are dark, cool areas on the Sun’s surface characterized by intense magnetic activity.

When the magnetic field lines near sunspots become tangled and snap, they release an enormous amount of energy in the form of a solar flare.

This sudden burst of radiation spans the entire electromagnetic spectrum, from radio waves to gamma rays.

Coronal mass ejections: The Sun’s plasma projectiles

In addition to solar flares, the Sun occasionally releases billions of tons of plasma and magnetic fields into space, known as coronal mass ejections (CMEs).

These colossal clouds of charged particles travel at speeds of up to several million miles per hour, potentially causing geomagnetic storms when they interact with Earth’s magnetic field.

Impact of solar storms on Earth

When a solar storm reaches Earth, it can cause a range of effects:

  • Aurorae: The charged particles from the Sun interact with Earth’s magnetic field, causing the beautiful displays of light known as the Northern and Southern Lights (aurora borealis and aurora australis).
  • Satellite Disruptions: Solar storms can damage or disrupt the operation of satellites, affecting GPS navigation, communication systems, and other technology that relies on satellite data.
  • Power Grid Failures: Strong geomagnetic storms can induce currents in power lines, potentially causing widespread blackouts and damaging electrical infrastructure.

Monitoring and predicting solar storms

Scientists continuously monitor the Sun using various instruments, such as the Solar Dynamics Observatory (SDO) and the Solar and Heliospheric Observatory (SOHO). These satellites provide real-time data on solar activity, allowing researchers to detect and study solar storms as they occur.

Predicting the timing and intensity of solar storms remains a challenge, but advances in solar physics and space weather modeling are improving our ability to forecast these events and mitigate their potential impact on Earth.

As we continue to explore the mysteries of the Sun and its effects on our planet, understanding solar storms becomes increasingly crucial for protecting our technology-dependent society and ensuring the safety of our space-based assets.

The full study was published in the journal Geophysical Research Letters.


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