Space super-storms are a serious worry when it comes to human technology because intense ones can cause blackouts and significant damage. Researchers have now worked out the statistical occurrences of these super-storms, and it turns out they are likely to happen more often than thought.
Space weather affects technology on Earth. Dramatic events can render useless satellites, power stations, and electronics. But even just minor events can chip away at our tech, slowly degrading them.
As reported in Geophysical Research Letters, a team led by the University of Warwick used measurements of the disturbances in Earth’s magnetic field taken in Australia and the UK. The set is known as the aa index. This data goes back to 1868, roughly 80 years earlier than other indices, which dramatically improves what we know historically of powerful super-storms.
According to the data a severe super-storm happened in 42 years out of 150 cataloged, 28 percent of the sample. More concerningly, a "great" super-storm occurred in six years out of 150, or 4 percent. That’s roughly one every 25 years.
“These super-storms are rare events but estimating their chance of occurrence is an important part of planning the level of mitigation needed to protect critical national infrastructure,” lead author Professor Sandra Chapman from Warwick’s Centre for Fusion, Space and Astrophysics, said in a statement.
“This research proposes a new method to approach historical data, to provide a better picture of the chance of occurrence of super-storms and what super-storm activity we are likely to see in the future.”
The most powerful recorded solar storm, the Carrington Event of 1859, falls beyond the aa index, but we have plenty of data on the great super-storm of 1989 that caused a major power blackout in Quebec. A near miss occurred in 2012 when a coronal mass ejection was released by the Sun, luckily moved in a different direction and did not hit Earth.
The message from the data shouldn’t suggest that we are owed one soon, or that there is one exactly every 25 years, however. It gives an idea of how likely a powerful storm is to happen in any given year. So a storm like the one from 1989 has a 4 percent chance to occur in any given year. Another Carrington Event has a projected value of 0.7 percent. It is concerning that the number is higher than thought, though, and it should be considered a reminder to invest in mitigation approaches.