Something New Under the Sun

Scientists are probing deep beneath the surface of our nearest star to calculate its profound effect on Earth

When a coronal mass ejection reaches Earth, solar particles stream along magnetic field lines, energize gases in the atmosphere and shine as norther lights. (Federico Buchbinder)
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On an uncharacteristically tropical morning in the San Francisco Bay Area, the ground shimmers with waves of heat, and it’s impossible to look to the sky without squinting. But the real heat is inside the Lockheed Martin Solar and Astrophysics Laboratory in Palo Alto. There, in a dark room stacked with computer processors, a high-definition view of the Sun fills nine conjoined TV screens to create a seven-foot-wide, theater-quality solar extravaganza.

Solar physicist Karel Schrijver types commands to start the show: an accelerated movie of a sequence of explosions that wracked the Sun on August 1, 2010. “This is one of the most stunning days I’ve ever seen on the Sun,” Schrijver says. He’s been looking at our nearest star for two decades.

“At the beginning this tiny little region decides it’s not happy,” he says, sounding like an astronomical psychiatrist coping with solar neuroses. He points to a flare, a modest spasm of whitish light. “Then, this nearby region begins to get unhappy, and it flares. Then a huge filament erupts and cuts through the [magnetic] field like a knife. We see this arc of glowing material, and it grows with time. A little filament under the arc says, ‘I don’t like that one bit,’ and it becomes unstable and goes off.”

Who knew the Sun has so much personality?

Within hours—sped up to minutes in the digitized replay—much of its magnetic field “gets upset,” Schrijver says, and rearranges itself, unleashing flares and vast belches of magnetized gas. The chain reaction is more vivid than any Hollywood depiction. “When we show these movies to our colleagues for the first time,” says Schrijver, “the professional expression is generally, ‘Whoa!’”

The torrent of images comes from the most advanced satellite ever to study the Sun: NASA’s Solar Dynamics Observatory, or SDO. Launched in February 2010, SDO stares at the star from a point 22,300 miles above Earth. The satellite’s orbit keeps it at a steady position in view of two radio antennas in New Mexico. Every second, 24 hours a day, SDO beams 18 megabytes of data to the ground. The high-resolution pictures, as well as maps of the Sun’s tortured magnetic fields, show the genesis of sunspots and the origins of their outbursts.

This solar movie should provide new insights into space weather—the impacts felt on Earth when the Sun’s ejections head our way. Sometimes the weather is mild. The August 1, 2010, eruptions set off colorful displays of aurora borealis over the United States two days later when a fast-moving storm of charged gas disturbed Earth’s magnetic field. But when the Sun truly gets angry, the northern lights can signal potentially disabling threats.

The most intense solar storm ever recorded struck in the summer of 1859. British astronomer Richard Carrington observed a giant network of sunspots on September 1, followed by the most intense flare ever reported. Within 18 hours, Earth was under magnetic siege. Dazzling northern lights glowed as far south as the Caribbean Sea and Mexico, and sparking wires shut down telegraph networks—the Internet of the day—across Europe and North America.

A magnetic storm in 1921 knocked out the signaling system for New York City’s rail lines. A solar storm in March 1989 crippled the power grid in Quebec, depriving millions of customers of electricity for nine hours. And in 2003, a series of storms caused blackouts in Sweden, destroyed a $640 million Japanese science satellite and forced airlines to divert flights away from the North Pole at a cost of $10,000 to $100,000 each.

Our modern, globally connected electronic society is now so reliant on far-flung transformers and swarms of satellites that a major blast from the Sun could bring much of it down. According to a 2008 report from the National Research Council, a solar storm the size of the 1859 or 1921 events could zap satellites, disable communication networks and GPS systems and fry power grids at a cost of $1 trillion or more.


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