Solar storms are not spread evenly through the years. The Sun runs on a rhythm of about eleven years, from quiet to busy and back. Knowing where we are in it tells you what kind of year to expect.
Module 2 showed the Sun's magnetic field being wound up like a spring. That winding is not a one-time event. It builds for years, the Sun breaks out in sunspots and eruptions, the tangled field finally unravels and flips over, north for south, and the whole thing starts again. One round takes about eleven years. Astronomers have counted sunspots since the 1700s, and this is cycle number 25.
Sunspots are the easy thing to count, so they are the yardstick. But they are not what reaches Earth. CMEs are.
In 2018, near the bottom of the cycle, NASA catalogued about one CME a week. In 2025, near the top, how many a week?
The cycle changes where eruptions come from, not only how many there are. Each oval below is the whole Sun unrolled flat for one year, with a dot where every CME launched. The lit middle is the side that faced Earth.
Our recordFrom the site's launch map: NASA's fitted direction for each CME, traced back to the Sun.
In the quiet years the few eruptions hug the equator. As the cycle climbs, they spread out into two wide belts either side of it.
Loading where the cycle stands…
The busy years bring most of the big storms, and the worst ones tend to come around the peak and for a few years after it. But the cycle only sets the odds. The Carrington storm of 1859 came in an unremarkable cycle, and the strongest storm in twenty years, in May 2024, came in a cycle smaller than average. One sunspot group is enough.
The site has three pages built on this rhythm: the solar cycle back to 1749, where the Sun shoots, and a calendar of every day since 2016.