Maybe it’s all a state of mind, I don’t know, but every spring as the sun gets higher and the air gets warmer, everybody seems to blossom into a better mood. Boys race their car engines, and girls encourage them by peeling off as many clothes as they dare. People stroll instead of trudge across the parking lot. Sunlight cheers, there’s no doubt about it.

Apart from light and warmth, which seem like reasonable byproducts of a fire that big, the sun might seem too far away – about 93 million miles – to concern us much otherwise. The farther away something is, the less it affects you, right?

Of course, the sun is a lot bigger than it looks, and it’s active. The steady stream of light that nourishes our bodies (and apparently our emotions) emanates from perpetual thermonuclear combustion, as if billions of atomic bombs were detonating every second. Weirdly, this steady state of explosion is called by astronomers a “quiet” aspect of the sun. The “active” sun is another world, so to speak, with far more to it than meets the eye.

Sometimes huge explosions called solar flares occur on the 10,000-degree surface. Tongues of gas and magnetic fields called coronal mass ejections also erupt from the surface, and longer-lived “prominences” of sweltering gas can linger in great flamelike sprays and themselves often blow up.

Solar flares occur near sunspots, which are dark, cooler patches on the photosphere (the sun surface). Sunspots were never seen until Galileo turned a telescope upward in the 1600s. It was soon noticed that they come and go in 11-year cycles. This year we’re approaching the minimum of the cycle, when few sunspots appear.

Being so far away, sunspots might seem like just another weird detail for obsessed astronomers, except that they’re signs of potential solar flares which, it turns out, affect the Earth in ways undreamed of before telescopes and electricity.

The quiet sun blows the solar wind – a gaseous flow of atomic particles – steadily over us. Normally our atmosphere and magnetic field shield us from it. But big solar explosions disturb the wind, energizing atomic particles, disrupting our magnetic field, and causing “geomagnetic storms.”

Visible things are made from these invisible events. One is the aurora borealis – the Northern Lights, which occur when bursts of energy penetrate the Earth’s magnetic field and accelerate ions that then give off light, evidence of unseen things happening elsewhere. They can cause beauties, and also disorder.

Solar storms have spiked radiation in our region of space to levels that could kill astronauts. Geomagnetic storms have disrupted navigation systems and communications satellites, causing radio and TV malfunctions. In March 1989 a huge solar storm induced ground currents that collapsed Hydro Quebec’s power grid and blacked out 6 million people’s electricity. A solar superstorm in 1859 overwhelmed Earth’s magnetic field and shorted out telegraph wires, causing fires. More strangely, geomagnetic storms degrade the homing abilities of pigeons.

Invisible events are affecting even more than your good spring mood. There is something awesome, something very significant, about auroras. I’m not sure what it is.