Evidence of unusual solar activity that potentially represents three huge solar storms has been discovered in ancient Assyrian cuneiform tablets. The magnetic storms documented in astrological reports correspond to tree ring data indicating events took place around 660 BC.
This potentially helps scientists to predict future magnetic storms from our sun—events that have the potential to cause major disruption to the technology systems on Earth we currently rely on.
Astronomers started observing sunspots with telescopes around 1610. These are dark patches that appear on the sun’s surface and are associated with solar flares—sudden explosions that send a huge amount of radiation out into space. If solar flares and coronal mass ejections (CMEs) are directed toward Earth, this radiation can result in geomagnetic storms. This is where the particles from the sun interact with Earth’s atmosphere, interfering with communication systems, satellites and power grids.
“These space weather events constitute a significant threat to a modern civilization, because of its increasing dependency on an electronic infrastructure,” scientists led by Hisashi Hayakawa, from Osaka University, Japan, said in a study published in The Astrophysical Journal Letters.
In recent years, scientists have been able to identify multiple extreme space weather events prior to 1610 by looking at radiocarbon in tree rings—including events around 775, 993 and 994 AD.
Hayakawa’s team focused on three events that appear to have taken place in the decades around 660 BC. “These events occurred far before the onset of instrumental observations, well outside the more modern range of wide observational coverage,” they wrote. “Therefore, in order to infer the general trend of solar activity and the occurrence of CMEs, candidate auroral records have been sought in historical documents around these events.
“The Babylonians and Assyrians had started astrological observations, at the latest, in the 8th century BC. Already in the 7th century BC, Assyrian kings had collected and received astrological reports from professional astrologers, to interpret the ominous meaning of observed celestial events.” The cuneiform records are rectangular clay tablets with inscriptions on them.
Researchers carried out a survey of auroral records kept by the Assyrians to see if there were events that correspond with scientific data regarding ancient solar activity. They found cuneiform tablets that held records of aurora dating between 680 and 650 BC.
These tablets describe unusual red skies, with one mentioning a “red cloud” and another saying that “red covers the sky.” The team believes these descriptions are likely the result of “stable auroral red arcs,” where magnetic fields excite electrons in atmospheric oxygen atoms to emit light. The researchers also point out that Earth’s magnetic north pole would have been closer to the Middle East than it is today, meaning events associated with solar activity would have been observed further south.
The team say they believe these tablets to be the “earliest datable records of candidate aurorae” that support the idea there was increased solar activity at this time.
Reconstructing activity on the sun thousands of years ago may help scientists predict future events. “These findings allow us to recreate the history of solar activity a century earlier than previously available records. This research can assist in our ability to predict future solar magnetic storms, which may damage satellites and other spacecraft,” senior author Yasuyuki Mitsuma said in a statement.