© Solar Dynamics Observatory/ESA/NASA
Flares erupting on the Sun in 2014.
An extreme form of solar storm, known as a solar proton event (SPE), struck our planet 2,679 years ago, according to new
research published today in
Proceedings of the National Academy of Sciences. If an event of such magnitude were to happen today, it would likely wreak havoc on our technological infrastructure, including communications and navigation. Lund University geologist Raimund Muscheler and his colleagues presented evidence in the form of elevated levels of beryllium-10 and chlorine-36 isotopes embedded within ancient Greenland ice cores.
It's now the third massive SPE known to scientists, the others occurring 1,245 and 1,025 years ago. This latest discovery means solar storms of this variety are likely happening more frequently than we thought-perhaps once every 1,000 years-but more data is required to create more reliable estimates.
SPEs happen in the wake of a massive solar flare or coronal mass ejection on the Sun. These stellar events send streams of particles, including high-energy protons, toward Earth, where they interact with the Earth's atmosphere, triggering reactions that increase the rate of radionuclide production, including carbon-14, beryllium-10, and chlorine-36 (radionuclides are unstable atoms with excess nuclear energy). Traditionally, SPEs have been detected as spikes of carbon-14 in tree rings, but they can also be spotted as spikes of beryllium-10 and chlorine-36 in ancient ice cores. The authors of the new study said scientists tend to overemphasize carbon-14 at the expense of searching for other markers, and that "efforts to find [SPEs] based solely on [carbon-14] data likely lead to an underestimated number of such potentially devastating events for our society."
Comment: Also relevant: Global Warming? Los Angeles experiences coldest February in 60 years
Storm breaks 135-year-old rainfall record for downtown Los Angeles