Diary

A new active region emerging from the far side of the Sun has significantly boosted the rate of solar flares. Yesterday saw 19 such events, including the first M-class flare in many days; the last time a flare of this class was observed was back on July 30—about three weeks ago. The corresponding sunspot group is already visible from Earth on the Sun's left limb and has even been assigned a catalog number: 4513. Visually, it still appears quite modest (so much so that it is unclear where all that energy is coming from), but it is possible that the bulk of its structure remains hidden—like an iceberg—and will only become visible later. As is well known, sunspots are created by strong magnetic fields that form deep within the Sun—at a depth of around 200,000 kilometers—before rising to the surface, making the iceberg analogy quite apt.

Current forecasts are cautious, but the prevailing view is that the active region is passing its peak and further intensification of activity is unlikely. However, it is worth waiting until the sunspots fully rotate onto the visible hemisphere so their structure can be properly analyzed.

Geomagnetic activity remains at the same elevated level seen over the past two days. Earth is still immersed in a stream of high-speed, high-temperature solar wind but appears to have reached an equilibrium with these external conditions; no geomagnetic disturbances have been observed for nearly 20 hours. Isolated spikes remain possible through Friday. By the weekend, however, space weather should return to normal regarding both flare frequency and geomagnetic activity.