The sun goes through a regular 11-year cycle that fluctuates between periods of rest and periods of activity. Scientists from NASA and NOAA have just announced that the sun has just passed its minimum and will increase in activity over the next few years, meaning we have entered a new round of the never-ending solar cycle.
We have observed sunspots for thousands of years, but it was not until the invention of the telescope that we could keep records of activity on the sun's surface. However, through these centuries-long observations, we were able to determine a special 11-year cycle. Over the course of 11 years, the sun has little to no sunspots and then steadily increases in activity before calming down to repeat itself again.
Astronomers suspect that sunspot activity is related to the sun's strong magnetic field. When the sun is calm, the magnetic fields are considered beautiful and straight, and extend from north to south as they do on Earth. But over time, the magnetic fields wrap up to form complex, tangled tissues that plunge in and out of the surface.
A sunspot appears where the magnetic fields hit the surface. But at some point the tangle gets too strong, and the magnetic fields break open, releasing currents of energy – and triggering furious explosions of explosions and coronal mass ejections. After releasing their anger, the magnetic fields resume their preferred north-south direction and the cycle begins again.
Sunspot observations suggest that the sun passed its absolute minimum sometime in December 2019. This emerges from a report by the Solar Cycle 25 Prediction Panel, a group jointly organized by NASA and NOAA.
The report is only now appearing as the sun varies from month to month. So it takes a good number of months before a fixed call can be made.
But here we are, a few months after the start of the new solar cycle, the 25th such cycle since we kept track of things.
This means that in the months and years to come, sunspots should become increasingly common and solar weather – including dangerous flares and storms – will become more frequent and will peak in 2025.
Even so, solar physicists suspect the impending spike in activity won't be that bad. The recent solar cycle peaks have been on the tame side (for reasons we don't understand) and we have no reason to believe that number 25 will be anything spectacular.
Even so, even a tame sun can be dangerous. Flares and coronal mass ejections pose a threat to space probes, orbiting satellites, and even electrical systems on Earth (when they get particularly nasty). However, the streams of particles emitted by the sun are responsible for the aurors in our atmosphere. Hence, aurora hunters should have better light shows to look forward to in the years to come.