Today, a large coronal hole is positioned directly facing Earth. Stretching across the Sun’s southern hemisphere, this structure is releasing a stream of high-speed solar wind now expected to interact with Earth’s magnetosphere.
NOAA has issued a G1 (minor) geomagnetic storm watch beginning later this weekend. While G1 storms are relatively weak, they can still enhance auroras in high-latitude regions and cause minor disruptions to satellite systems, navigation, and radio communications.
What is a coronal hole?
Coronal holes are regions in the Sun’s outer atmosphere (corona) where the magnetic field opens outward into space, rather than looping back onto the solar surface. This configuration allows plasma to escape more efficiently, forming high-speed solar wind streams. In ultraviolet images from spacecraft like NASA’s Solar Dynamics Observatory (SDO), they appear as dark patches due to lower density and temperature.
These features are more frequent and often more expansive during solar maximum, the period of peak solar activity in the Sun’s 11-year cycle. While not associated with explosive solar flares or coronal mass ejections (CMEs), coronal holes are a steady source of space weather variability.
