On 11 November 2025, a powerful X5-class solar flare erupted from the Sun at 10:10 UTC, associated with a fast coronal mass ejection (CME) directed towards Earth.
The event — designated Ground Level Enhancement 77 (GLE77) — was one of the strongest solar energetic particle events of Solar Cycle 25, detected by a network of instruments in space and on the ground (so far confirmed):
- Solar Orbiter
- SoHO/EPHIN & ERNE
- GOES satellites
- Neutron Monitor network
Key Highlights:
- Flare time: 10:10 UTC
- Flare class: X5
- GLE detected within minutes
- Oulu NM increase: ~60% above baseline
- South Pole NM: exceptional ~120% rise
- Event clearly seen up to Mexico NM (8.28 GV) – proving the presence of very energetic particles across latitudes
- CME expansion captured in SOHO/LASCO & STEREO/COR imagery
Within the SPEARHEAD project, which focuses on high-energy particles, four GLEs have already been observed during its timeline, marking an active and scientifically rich phase of Solar Cycle 25.
GLE77 stands out as a rare, high-intensity solar particle storm that connects ground-based and space-based observers.
This was one of the most energetic solar particle events of the cycle – a vivid reminder of how solar activity ties together our Sun, Earth, and interplanetary environment.