Nowadays it seems we’re trained to be afraid. Reports that the sun’s magnetic field is flipping have caused not a few ripples of excitement. Some popular media report responsibly. Others play on fears, claiming that the magnetic field’s reversal means we’re in for some stormy weather.

The good news? We’re not doomed.

At just shy of 100 million miles away, our solar dance partner might seem too distant for relatively small events within it to have much impact on the earth. But the sun constantly blows a blistering ionized “plasma” gas toward our planet, its temperatures approaching 200,000°F. Of course, this solar wind’s temperature decreases as it travels farther from the sun, and it is so light that, for the most part, it is merely interesting. But sometimes the wind blows hot, dense, and fast enough to cause problems on the earth—along with glorious auroral light shows.

Solar Magnetic Wind and Sunspots

The solar magnetic wind is invisible to the eye, but one can get an idea of what is going on simply by looking at the sun, because sunspots influence the solar wind. One can sometimes see large sunspots (which may be 12 times the diameter of the earth) with the naked eye, but it is not advisable to try, because the sun blows off not only plasma but also a large amount of electromagnetic radiation similar to the light from a welding torch. Looking at sunspots probably contributed to Galileo’s blindness. Appropriate equipment is advisable.

Around 28 B.C. Chinese astronomers recorded spots on the sun. The Greek philosopher Anaxagoras might have seen a spot in 467 B.C. From around the sixteenth century, physicists began systematically collecting daily records of sunspot numbers. We now have about 500 years of continuous records of these dark pimples on the face of the sun.

In the nineteenth century physicists recognized a connection between sunspots and our planet that they’d not realized before: magnetic activity observed by compasses sometimes spiked dramatically when sunspots were numerous.

It was still mainly an academic interest until the dawn of the space age, when it became clear that sunspots are associated with many disturbances on earth. We discovered that the sun has an atmosphere, and that the earth resides within it! This suggests that whatever happens on the surface of the sun affects us directly. Thus was born the area of research known as space weather—my specialty as a physicist.

Space weather researchers study the direct effects of solar activity on our technologies. Strong, but for the most part not destructive, effects have been observed in global telecommunications, electric power grids, navigation, human spaceflight, and satellite reliability.

Solar Cycles, Space Weather, and Earth Climate

It is difficult to predict space weather, and we often need to rely on proxies like sunspots. Sunspots usually oscillate between high and low numbers over a period of about eleven years. Data from various satellite experiments support the idea that the rising and falling sunspot numbers have something to do with magnetic activity within the sun. Sunspots signal changes deep below the sun’s surface. And usually the amount of intense space weather correlates well with the number of sunspots.The sun has a strong magnetic field that, because we are in its atmosphere, reaches out to touch the earth. Near the time of solar maximum—when sunspots reach their peak—something interesting happens within the sun. Overall solar magnetic activity decreases, and then the sun’s magnetic field turns on its head! Then the sunspots slowly begin to vanish.Since we are cruising within the solar atmosphere, we can easily detect the flip. Data for several hundred years show that the regular flipping, every eleven years or so, is more like a comforting tick-tock of a grandfather clock than the ominous tick-tick of a time bomb.

The flip generates interest because of that connection with space weather near its occurrence. Bad space weather can happen any time, but it is more common during solar maximum. Massive space storms make compass needles race more erratically than ever, and auroras blaze bright and ubiquitous. No big deal.

But today we often depend on continuous access to technologies sensitive to electromagnetic fluctuations. Think of a space storm, which affects everything in the sun’s atmosphere—including the earth—as an electrical thunderstorm on a solar-system scale. Alarming reports about impending disasters due to the regular tick-tock of the solar magnetic field are unjustified. But unplugging, or electronically hardening, sensitive equipment, as we do during thunderstorms, may be prudent.

There is also an apparent connection between the number of sunspots (and hence solar wind and interplanetary magnetic field) and global climate. The highs of the current solar activity cycle are approaching the weakest in a century—signaled by the paucity of sunspots. If this continues, it may signal a future low period for the sun like what helped cause the “Little Ice Age” from the mid-16th to mid-19th centuries, with its coldest periods characterized by the Maunder (about 1645–1715) and Dalton (about 1790–1830) minima. Global cooling could replace the modest warming that prevailed from the mid-1970s to the mid-1990s and the relatively stable global temperatures of about the last 16 years.That would be nothing new. Global warming and cooling, like sunspot cycles, have occurred cyclically (with shorter and longer cycles superimposed) throughout the earth’s history.

Featured Image Courtesy of Feelart/freedigitalphotos.net