Scientists have found evidence of a mega-blast of radiation from the Sun that hit Earth more than 2,500 years ago.
The researchers behind the new international study, led by researchers from Lund University, have found evidence in Greenland ice core samples that suggest a very powerful solar storm occurred in 660 BCE.
This storm would likely not have shown any appreciable signs to people alive at the time, other than associated geomagnetic storms triggering strong aurorae at abnormally low latitudes. However, “If that solar storm had occurred today, it could have had severe effects on our high-tech society,” says Raimund Muscheler, professor of geology at Lund University.
Researchers have also identified two other large events from the past, which left evidence in both Greenland ice cores and tree rings. One of these, which occurred between 774 and 775 AD, was comparable in its magnitude to the one in 660 BC.
Scientists are now working to understand how common the extreme events are, something that could help us plan for big solar storms in future.
Solar forecasters see us entering a period of prolonged solar decline –a Grand Solar Minimum— within the next few years. Perversely, a reduction in solar activity weakens Earth’s magnetic field (our planet’s main defence against the sun) but powerful solar flares still occur, meaning we’ll be hit when our shields are down.
The sun is currently within the solar minimum of its weakest cycle in over 100 years (cycle 24), but as it begins its ramp-up towards the solar maximum of cycle 25, many are calling this as the possible time-frame for the next big bombardment — around 2023.
Even if Solar Cycle 25 is greatly diminished, as NASA is predicting, it will still be capable of firing off a super-flare or two.
In addition, as earth’s magnetic pole continues its wander/excursion/reversal, the magnetosphere is waning even quicker.
These two independent factors occurring simultaneously, a Grand Solar Minimum and a Pole Shift, mean any solar outburst will have an even larger impact on our planet and the fragile modern infrastructure we’ve built upon it.
For the scientific paper, click here.
Grand Solar Minimum + Pole Shift