A solar flare, an explosion on the sun that happens when energy stored in “twisted” magnetic fields is suddenly released
NASA/SODATA/Alamy
According to records preserved in Alpine tree trunks, it is believed that the most powerful solar storm ever hit Earth 14,300 years ago. The extent of damage that a similar storm could cause today is uncertain, but it is theoretically possible for electricity grids to be knocked offline for months and for all satellites to be destroyed.
In 2012, evidence was discovered in tree trunks by Fusa Miyake at Nagoya University in Japan, suggesting extremely powerful solar flares from the sun. These flares, known as Miyake events, have been found to have caused a spike in the level of radioactive carbon in trees that dates back many centuries.
Since then, at least nine probable ancient solar storms have been identified using this method.
A recent study by Tim Heaton at Leeds University in the UK and his colleagues has uncovered evidence of the largest solar storm ever recorded. This storm, almost twice as large as the next largest Miyake event, was found in pine tree trunks in the southern French Alps.
The potential consequences of a similar storm today are uncertain. Some experts believe it could be catastrophic, causing month-long blackouts to half the globe and permanent damage to satellite solar panels. However, there is still a lot of uncertainty and differing predictions about the level of disruption such a storm would cause.
Heaton and his team conducted their study by examining 140 tree trunks buried in a bank of the Durance river in Provence. By comparing the tree rings and constructing a timeline of when each tree lived, they were able to date a significant spike in the presence of carbon-14 to 14,300 years ago. This spike was also consistent with elevated levels of beryllium found in Greenland ice cores, which is produced in a similar way to carbon-14.
Unfortunately, there is no historical event to compare the magnitude of this storm to, as the largest solar storm on record, known as the Carrington event in 1859, was much smaller than the Miyake events and would not even register a blip in the radiocarbon record.
While we now know of 10 Miyake events in the past 15,000 years, their frequency and predictability remain uncertain. It is also unclear what changes the sun undergoes to produce these events, as they do not align with previously understood behavior patterns.
Further research is needed to fully understand these solar storms and their potential impacts. The radiocarbon spike alone cannot provide information about other behaviors of the sun during solar storms, such as high-energy gamma rays or plasma expulsions.
According to Raimund Muscheler at Lund University in Sweden, the radiocarbon spike is only produced from the sun’s high-energy particles, like protons, and does not reflect the full range of solar storm behaviors.
Muscheler believes that there is much more to learn about these events and that the largest solar storm observed so far may just be the tip of the iceberg.
