Ever wondered what we’re losing as ice sheets around the world thin out, calve off, and melt into the sea? Polar bear habitat to be sure, and miles of coastline as sea levels rise. But we’re also losing a record of Earth’s deep geological and astronomical history.
A reveals new evidence found in ice cores extracted from the Greenland ice sheet. The researchers, led by geologist Paschal O’Hare, found telltale signs of a gigantic solar storm dating back to 660 B.C.
High concentrations of two radionuclides, beryllium-10 and chlorine-36, suggested the storm was 10 times more powerful than the strongest solar proton event (SPE) ever recorded by instruments, which happened in 1956. The study also claims, “it is only the third such event reliably documented and is comparable with the strongest event detected at A.D. 774/775.”
Two years ago, scientists examining tree rings noticed a surge in the isotope carbon-14 at the 660 B.C. mark. A potential indicator of an SPE, carbon-14 could also result from a supernova or solar flare, which are more common, cosmogenically speaking. O’Hare’s ice core evidence showing a spike in 10Be and 36Cl in the same time period strengthens that storm by several orders of magnitude.
Solar proton events occur when releases sudden blasts of energetic solar particles that engulf Earth’s magnetosphere. The particles are supercharged by a sort of cosmic fuel injection—what the study characterizes as “shock waves associated with coronal mass ejections” (which sounds awesome regardless of the actual astrophysics involved).
In extreme cases like these, the particle streams infiltrate the magnetosphere, blending with Earth’s atmosphere and coating forests and ice sheets in radionuclides for scientists to contemplate thousands of years later.
The prospect of a solar proton event today brings with it a whole host of concerns virtually non-existent in 1956, not to mention 660 B.C. The impact on our global technological infrastructure would be, in the study’s words, “potentially devastating.”
This is when scientific expeditions into the far reaches of North Greenland suddenly have everything to do with astronomy which, in turn, has everything to do with safeguarding our communication networks and navigation systems and commercial aircraft operations and national security.
You can thank that ice core laced with beryllium-10 and chlorine-36.