In Boulder, Colorado, eleven people take turns doing something our mothers told us never to do; they stare continuously at the sun. Fortunately, they watch through the eyes of satellites, thus avoiding fried retinas. These eleven are space weather forecasters at the National Oceanic and Atmospheric Agency’s (NOAA’s) Space Weather Prediction Center (SWPC).
Space weather is any solar activity that sends plasma and radiation towards Earth. Although we don’t pay as much attention to it as terrestrial weather, space weather is becoming more important the more we use technologies that rely on satellite communication. Self-driving cars and drones, for example, rely on location data from the Global Positioning System, which space weather can disrupt.
To learn more, I spoke with Rob Steenburgh, acting forecasting lead of NOAA’s SWPC, and later sat with two forecasters during their shift.
Steenburgh holds degrees in meteorology and physics, and he looks like a movie space scientist, wearing dark-rimmed glasses and a checkered shirt that yearns for a pocket protector. He said three things about the sun cause space weather. It generates magnetic fields, it pushes those magnetic fields upwards by convection, and—because it’s not solid like Earth—it rotates faster at its equator than its poles, contorting the magnetic fields as it spins.
“It’s just like twisting a rubber band,” Steenburgh said, “Twist it enough, it breaks.” When the sun’s magnetic fields break, reorganize, and reconnect, they release massive amounts of energy, many times that contained in a nuclear bomb. That energy is what causes space weather.
Entering the SWPC forecasting office is like boarding a spaceship. Fourteen flat-screen monitors hanging on the front wall split the sun’s rays into a rainbow of solar images. Each image uses different wavelengths of light to expose different layers of the sun, much like doctors use X-rays to look at our bones under folds of wrinkly skin and jiggly fat. Pink and gold and teal suns line the wall and illuminate the dim room where forecasters hold vigil over the sun twenty-four hours per day, every day of the year.
At the back of the room, two large windows give tour groups a view into the center. “It never fails that you’re about to stuff your mouth and there’s forty people out there taking pictures of you,” said Chris Smith, one of the two forecasters on shift. He’s big and looks every bit an ex-Air Force guy, Birkenstocks notwithstanding. Sure enough, a group huddles outside the windows as if about to see lions at the zoo.
Two workstations divide the forecasting office, each surrounded by more monitors, double-stacked and plotting countless variables in as many different colors. Smith was at the left station, in charge of predicting the space weather for the next few days. John Lash, the other forecaster on duty, was at the right station, in charge of reviewing current weather data and issuing warnings and alerts. Lash, like most of the forecasters, is also ex-Air Force, but he’s less imposing than Smith, with a shorter stature and a baby face. Smith joked that Lash looks twelve, though they each have over ten years’ experience.
One of their most important tasks is to analyze sunspots, cooler and darker regions on the sun. If you were to somehow transport a sunspot away from the sun, it would glisten in space on its own. But on the sun, surrounded by much hotter gas, a sunspot appears black. Forecasters follow the dark spots as the sun rotates, categorizing them based on size, quantity, and magnetic complexity. Overlapping spots with tightly wound magnetic fields have a higher probability of snapping like Steenburgh’s rubber bands.
When they do, solar flares spew electromagnetic radiation at the speed of light. When they’re aimed towards us, flares bring radio blackouts in about eight minutes. Solar flares are similar to earthquakes in that they have immediate impacts, but it’s difficult to predict exactly when, or if, they’ll blow. When they do, forecasters have little time to warn those who need to know.
In May of 1967, such a blackout caused U.S. military commanders to believe Russians were jamming communication signals to obscure a possible nuclear missile attack. Fortunately, nascent space weather monitoring programs alerted military personnel before they could respond with an apocalyptic counterattack.
Although The Cold War ended decades ago, space weather forecasting continues to be an important part of national defense. Indpendently of NOAA, the U.S. Air Force monitors space weather to protect military assets that defend us. When he was still in the Air Force, Smith recalls getting a phone call from Marines in Afghanistan, gunshots sputtering in the background, wondering if space weather was responsible for their communication problems. It could have been, but that day it wasn’t.
The National Aeronautics and Space Administration (NASA) also closely follows space weather, receiving daily updates from NOAA. One of NASA’s primary concerns is high-energy protons from the sun that can embed in satellites, damaging their circuitry—or worse—penetrating astronauts and damaging their DNA. During these “proton events,” which often accompany solar flares, NASA limits satellite maneuvers and extra-vehicle activities that put astronauts outside of the international space station.
When I met with Steenburgh, he told me he once received an email from a man wondering whether a proton event ricocheted off his sister-in-law into a jar of coins on his counter, causing it to vibrate. He laughed and said, “That did not happen.” Earth’s atmosphere protects us from much of the sun’s radiation. Radiation from proton events becomes a problem on Earth only at high altitudes within polar regions. Occasionally, airlines need to reroute flights to minimize long-term exposure risks to crew members who routinely fly over the poles.
If solar flares are like earthquakes, coronal mass ejections, or CMEs, are like tsunamis. CMEs often trail flares, bringing severe space weather to Earth but they travel more slowly, allowing more warning time. Steenburgh called CMEs “interplanetary projectile vomiting” and said, “sometimes that puke is aimed at the earth. Billions of tons of material moving at millions of miles an hour.” The “puke” is clouds of plasma reaching Earth anywhere between about eighteen hours and several days.
Plasma is the fourth and most energetic state of matter. Just as energy melts solid to liquid and vaporizes liquid to gas, nuclear levels of energy rip gaseous atoms apart, releasing electrons and protons into ionized gas. That’s plasma.
The charged electrons and protons form magnetic fields that forecasters analyze to determine the strength of a CME. One difficulty is that forecasters are unable to analyze the plasma cloud until about an hour before it reaches us, when it encounters a satellite floating between the earth and the sun. Forecasters read data taken from the satellite to understand the cloud’s magnetic field, which determines how the CME will interact with Earth’s magnetosphere, the protective sheath of magnetic fields around our planet. To affect us, the cloud has to be oriented in a way that grabs onto our magnetosphere, like two magnets pulling together.
“If it’s aligned and it sticks, you get a big geomagnetic storm,” Steenburgh said, and the charged particles slide along Earth’s magnetic field lines to the north and south poles. Similar to how terrestrial forecasters categorize hurricane severity, forecasters rank geomagnetic storms. The strongest—G5 storms—can knock out power grids as they did in 1989, turning out the lights across the entire Canadian province of Quebec. Weaker G1 storms create a pretty aurora show but little else.
According to Smith, people sometimes call the SWPC asking whether they’ll be able to view the aurora lights. He said someone once called from Alaska during the summer—a time when the sun doesn’t set there—asking if they’d be able to see northern lights that night. He told them to “try in about six months.” Even when it is possible to see the aurora, forecasters can’t pinpoint the best place; so, don’t bother calling them to ask.
On the wall of multi-colored suns, one image is an orange fireball with flames many times the size of our planet licking space around the sun’s edge. More than one million Earths would fit inside the sun, but it’s difficult to feel the scale on a screen the size of a fireplace.
Another cream-colored image normally shows sunspots, but it’s empty right now. All is calm on the sun because we’re in the trough of the eleven-year solar cycle, called solar minimum. Steenburgh called it “the doldrums.” Scientists don’t completely understand why sunspot activity follows an eleven-year sinusoidal curve, but they believe it’s analogous to variations in Earth’s oceanic currents.
Despite being solar minimum, space weather still crops up. Sunspots form, but much less frequently. And coronal holes, which Steenburgh described as “a big fire hose of high-speed solar wind,” tend to be stronger in this part of the cycle. Coronal holes cause geomagnetic storms by blasting us with plasma at speeds up to eight hundred kilometers per second, or almost two million miles per hour.
That day in the forecasting office, solar wind puffed plasma towards Earth at about half that speed, which is pretty typical. To Smith and Lash, it was like a calm breeze at the beach, perhaps a bit boring. They were not hoping for cataclysmic space weather, but with no activity, their shifts drag on. Things will liven up when the solar cycle approaches its apex. When will that be?
Smith said, “Come back in five years.”