Solar storms are caused by disturbances on the Sun that send charged particles into space. When those particles hit the Earth’s magnetosphere, that’s when the storm erupts. The particles can come from coronal mass ejections (CMEs), co-rotating interaction regions (CIR), and coronal holes that emit a high-speed (twice as fast) solar wind stream.
Solar storms powerful enough to cause failure of electronic equipment, including aviation and communication equipment, power grids and satellites, are not so isolated or rare phenomena: They hit Earth every 25 years, according to a new study by a team. by scientists from the University of Warwick and the British Antarctic Survey and published in the journal Geophysical Research Letters. And even more: less strong solar events -although dangerous- take place, approximately every three years.
In summary, scientists have identified two types of powerful magnetic storms:
Large super storms, the most powerful that occur every 25 years on average
Severe , weaker storms, occurring every three years
The analysis, which used historical data from the last 14 solar cycles, to expand on previous scientists’ estimates of the probability of super space storms, showed that “severe” super space storms have occurred 42 times in the last 150 years, and the major superstorms occurred 6 times within those 150 years.
Solar cycles
Scientists have been able to detect superstorms dating back 150 years by examining magnetic field records at opposite ends of the Earth (UK and Australia). This result was possible thanks to a new way of analyzing historical data, from the last 14 solar cycles, long before the space age began in 1957, instead of using the last five solar cycles that are commonly used in this type of analysis. .
These solar or geomagnetic storms can be triggered by solar flares, which explode on the Sun during years of high solar activity and can cause power outages, shut down satellites, disrupt aviation, and cause a temporary loss of GPS signals and radio communications.
“These super storms are rare events, but estimating the probability of their occurrence is an important part of planning the level of mitigation necessary to protect critical infrastructure in countries. This research proposes a new method to address historical data, to provide a better picture of the possibility of super storms and what activity we are likely to see in the future, “explains Sandra Chapman, leader of the work.
Carrington Event of 1859
The largest solar super storm in recorded history is known as the Carrington event and took place in 1859. This storm shut down some telegraph systems in different parts of the world, started some fires and even affected some telegraph operators. It is estimated that if a storm as powerful as the Carrington event occurred today, it would cause thousands or even billions of euros in damage. The Carrington event was not part of the study, because the data the researchers analyzed did not go back that far, but that storm could be considered a “super solar storm.”
Considering that technology makes us more dependent on our current lives, understanding and predicting space weather is a priority. Ships like SDO (Solar Dynamics Observatory) or the Parker Solar Probe aim to increase our understanding of the Sun and the ability to predict these dangerous geomagnetic storms.
Referencia: S.C. Chapman, R.B. Horne, N.W. Watkins. Using the aa index over the last 14 solar cycles to characterize extreme geomagnetic activity. Geophysical Research Letters, 2020; DOI: 10.1029/2019GL086524
