Extreme solar storms could affect Earth’s technology far more than previously thought, according to a NASA-led study challenging a decades-old assumption about how our planet responds to severe space weather.

Scientists have long believed Earth responds only so strongly as the solar wind intensifies. However, researchers now suggest this apparent limit may be an illusion caused by measurement uncertainty and a statistical quirk. The findings, published in Nature , suggest the stronger the solar wind gets, the stronger its effects on Earth may become, with no known upper limit so far.

Solar Storm Effects May Have No Known Limit

The solar wind striking Earth can cause aurora — the northern and southern lights — but it can also intensify electrical currents in the upper atmosphere, potentially affecting satellites, communications and navigation signals.

Previous observations suggested those currents increase as the solar wind strengthens before eventually leveling off. A team led by space physicist Nithin Sivadas of NASA’s Goddard Space Flight Center argues that this apparent limit comes from uncertainty in how the solar wind is measured.

“The issue is that most solar wind measurements are taken by spacecraft located a million miles closer to the sun than Earth is,” NASA explained in a release about the study.

Measurement Error May Create False Limit

The solar wind can change considerably between where it is measured and when it reaches Earth. Changes in its speed, structure and magnetic field mean measurements taken far from Earth do not perfectly represent the solar wind that actually reaches and interacts with our planet.

This means an extremely strong solar wind reading taken far from Earth may overestimate the strength of the solar wind that actually reaches our planet. That can make it appear that Earth has stopped responding to increasingly powerful solar wind when, in reality, the solar wind reaching Earth is weaker than the original measurement suggested.

The team analyzed evidence from more than one million solar wind measurements, including observations from NASA’s Magnetospheric Multiscale (MMS) and Time History of Events and Macroscale Interactions during Substorms (THEMIS) missions closer to Earth.

MMS uses four spacecraft flying in formation to investigate magnetic reconnection, a process in which magnetic fields break and reconnect, releasing energy and allowing solar wind energy to enter the region of space controlled by Earth’s magnetic field. THEMIS, originally launched with five probes to study disturbances linked to auroras, now uses three spacecraft to monitor near-Earth space and how it responds to changing conditions.

These closer measurements showed a more direct relationship between solar wind strength and Earth’s response.

Extreme Solar Storms Could Have Twice The Impact

After accounting for measurement errors, researchers found that Earth’s response continued to grow as the solar wind became stronger.

Their analysis suggests the impact of extreme storms could be as much as twice what previous interpretations implied when the solar wind is very strong.

The findings could change how scientists assess the risks that extreme space weather poses to satellites, power systems, communications and navigation technology. They could also force researchers to reconsider decades of theories about how Earth responds to the most powerful solar storms.

‘Worst-Case Scenario’ Solar Event

A paper last year examined a massive solar particle storm during the last Ice Age that was about 500 times stronger than any modern solar storm . A study of tree rings in the French Alps revealed evidence of an extreme spike in radiocarbon corresponding to 12,350 B.C. during the final stages of the last Ice Age. This was a solar particle storm, during which a burst of fast-moving, highly energetic protons caused a solar radiation storm around Earth. In modern times,, there is no close rival; the 2005 solar particle storm is the strongest ever recorded by science, but it was 500 times weaker than the one in 12,350 B.C.

Wishing you clear skies and wide eyes.