In 2024, the Sun put on one of its most dramatic shows in decades.
A single highly active region on its surface unleashed the strongest solar storm in more than 20 years, lighting up skies with brilliant auroras and disrupting modern technology on Earth.
Now, scientists say their unprecedented observations of this region could help improve future space weather forecasts.
Normally, studying the Sun is a bit like watching a spinning globe through a narrow window.
The Sun rotates once every 28 days, and from Earth we can only see any active region for about two weeks before it disappears from view on the far side. After another two weeks, it rotates back again.
That limitation changed with the arrival of the Solar Orbiter spacecraft, launched by the European Space Agency in 2020.
Unlike earlier missions, Solar Orbiter travels around the Sun on a wide orbit, allowing it to observe areas that are hidden from Earth. Between April and July 2024, it followed an unusually intense active region for far longer than ever before.
This region, known as NOAA 13664, became infamous in May 2024 when it rotated into Earth’s view and triggered massive geomagnetic storms.
These storms caused spectacular auroras that were visible far beyond their usual polar zones, even reaching Switzerland. It was the most intense solar activity seen since 2003.
To fully understand what was happening, an international team led by researchers at ETH Zurich combined data from two spacecraft. Solar Orbiter monitored the far side of the Sun, while NASA’s Solar Dynamics Observatory observed the side facing Earth.
By stitching these views together, the scientists were able to follow the same solar region almost continuously for 94 days — the longest uninterrupted observation ever achieved for a single active region.
The team watched NOAA 13664 from its birth on April 16, 2024, through its growth and increasing complexity, until it finally faded away in mid-July.
Over time, its magnetic field became more tangled and intense. These twisted magnetic structures store enormous amounts of energy, which can suddenly be released as solar flares and powerful eruptions that blast charged particles into space.
Such solar storms are more than just a visual spectacle. They can disrupt power grids, interfere with radio and GPS signals, increase radiation exposure for aircraft crews, and damage satellites. In May 2024, the storm even affected digital agriculture, disrupting satellite-guided farming equipment, drones, and sensors, leading to lost workdays and economic damage for farmers.
By tracking this region through multiple solar rotations, scientists gained new insight into how dangerous solar storms develop. While researchers still cannot predict exactly when or how powerful a solar eruption will be, these findings mark a major step forward.
Future missions aim to build on this progress. A new ESA spacecraft called Vigil, planned for launch in 2031, will focus entirely on space weather monitoring. With better observations, scientists hope one day to give earlier and more reliable warnings — helping protect the technology modern life depends on from the Sun’s occasional outbursts.
Source: ETH Zurich.
