Once-rare displays of Northern Lights at southerly latitudes look set to continue for the foreseeable future as scientists confirmed that August saw the sun at its most active for 23 years.
The average number of sunspots reached 215.5 in August, according to the Solar Influences Data Analysis Center at the Royal Observatory in Belgium. It’s the highest number since Sept.-Dec. 2001, according to SpaceWeather.com. July’s total was 196.5. Last month, NOAA’s Space Weather Prediction Center issued a preliminary statement that solar activity is at its highest since March 2001.
Magnetic Activity
The sun’s magnetic activity—the origin of the solar wind and the resulting bright aurora displays—is calculated daily by counting sunspots on its surface. Sunspots are magnetic disturbances on the sun’s surface that can be as big as Earth.
The number of sunspots on any day indicates how magnetically active the sun is. They’ve been counted every day since 1610, which has helped astronomers calculate that the sun’s magnetic activity waxes and wanes through an 11-year solar cycle. The sun is cirrently closing in on “solar maximum”—the peak of that cycle.
Solar activity is currently at a 23-year high, with Solar Cycle 25 more active than Solar Cycle 24, which occurred from 2009 through 2019. It’s now approaching the strength of Solar Cycle 23, which occurred from 1996 to 2008.
When Is ‘Solar Maximum?’
On May 10, 2024, a geomagnetic storm caused aurora displays worldwide and was rated as G5—the most intense. That had not been seen since Oct. 31, 2000.
Does this mean “solar maximum” is upon us? That’s impossible to know. The date of solar maximum can only be confirmed years after it’s happened when a definite wane in solar activity has been observed. NOAA’s Space Weather Prediction Center originally predicted a peak of just 115 sunspots for the current solar cycle’s solar maximum. Still, the current consensus forecast is for the solar maximum to occur in July 2025.
Why Sunspots Are Important
Sunspots are significant for aurora-chasers because they are the source of solar flares, powerful bursts of radiation that travel at the speed of light. These flares are often followed by coronal mass ejections that energize the solar wind, leading to geomagnetic storms on Earth. The latter can cause auroras in the northern and southern hemispheres.
When charged particles from these events interact with Earth’s magnetic field, they create beautiful displays of green and red light known as the auroras. These phenomena are typically visible in the northern hemisphere near the Arctic Circle at around 65 degrees north (Alaska, northern Canada, and northern Scandinavia). However, during intense geomagnetic storms, the auroras can be visible at even lower latitudes, down to 40 degrees north or further south.
That’s what’s happening more and more at the moment—and the good news is that it looks set to continue for at least another year, perhaps two.
Wishing you clear skies and wide eyes.
