Sunspots surge to 23-year high as solar maximum continues to intensify far beyond initial expectations

The number of black spots peppering the sun's surface in August was the highest for almost 23 years, new data shows. The latest sunspot count was more than twice as high as initial forecasts predicted and is another clear sign that the sun's explosive peak, or solar maximum, is likely well underway — and will be far more active than scientists initially thought.

Sunspots are regions of the sun's surface where surges of electromagnetic radiation break through the star's magnetic field, creating relatively cool patches that appear black to us thanks to an optical illusion. Along with the size and frequency of solar flares and coronal mass ejections, sunspot numbers indicate the progress of the sun's roughly 11-year solar cycle.

During the sun's least active phase, or solar minimum, there are very few or occasionally no sunspots. For example, in late 2019, shortly before the start of the current solar cycle (Solar Cycle 25), there were 40 consecutive days with no visible sunspots. But as the sun's magnetic field gets entangled with itself and weakens, sunspot numbers quickly climb before peaking during solar maximum. During this active phase, the sun's magnetic field eventually snaps and completely flips, which triggers a falling-off period of solar activity and a decrease in sunspots until the whole cycle restarts.

In August, there was an average of 215.5 daily sunspots on our home star's surface, according to the Space Weather Prediction Center (SWPC), which is jointly run by the National Oceanic and Atmospheric Administration and the National Weather Service. The last time the monthly sunspot number was this high was September 2001, during the solar maximum of Solar Cycle 23, when the average was 238.2.

The number of sunspots peaked on Aug. 8, when up to 337 sunspots were observed on the sun, which is the highest total in a 24-hour period since March 2001.

These numbers indicate what some scientists have already suspected — that we have entered solar maximum. However, we can't be certain of this until long after sunspot numbers begin to drop again.

Related: 15 signs the sun is gearing up for its explosive peak — the solar maximum