'Sun is active again': What high-speed solar winds at 700 kmph and quiet sunspot mean for Earth
Produced by Tarun Mishra
Produced by Tarun Mishra
Between the weekend and May 5, 2025, Earth experienced a burst of high-speed solar wind, with particles travelling at over 700 kilometres per second. This led to minor G1-class geomagnetic storms and visible auroras in high-latitude regions, including parts of northern United States and Europe.
The solar wind activity originated from a large coronal hole on the Sun’s surface. Coronal holes are areas where the magnetic field lines open up, allowing charged particles to escape and stream towards Earth, often causing geomagnetic effects.
The interaction between the high-speed solar wind and Earth’s magnetic field triggered geomagnetic disturbances. These resulted in bright auroral displays that extended farther south than usual, indicating the impact of the ongoing space weather activity.
Despite its size and visibility, sunspot AR4079 has remained unexpectedly calm. Typically, such large sunspots produce solar flares; however, AR4079 has so far emitted only weak C-class flares, leaving scientists puzzled.
One of the key features of AR4079 is a "light bridge"—a bright structure that runs through the dark core of the sunspot. Light bridges suggest complex magnetic configurations below the surface and may be precursors to solar flares. However, not all such features result in explosive activity.
While there have been no recent coronal mass ejections (CMEs) directed at Earth, continued solar wind activity could further disturb Earth’s magnetosphere. Scientists are monitoring for any changes in AR4079’s behaviour that might signal stronger flare activity.
The enhanced solar wind continues to compress Earth’s magnetic field, raising the potential for additional geomagnetic disturbances. These events can affect satellite communications, GPS systems, and power grids, prompting ongoing observation by space weather agencies.