At some point, we all learn—usually the hard way—not to stare directly at the sun. It’s just as well; we’d only see one side of its face peering down at us, from very far away. But there's a lot of activity going on in that giant orb, and NASA's giving it the attention it deserves. Its mission STEREO is designed to collect close-up solar scenes, and—as if in deference to Hollywood's latest schtick—turn them into 3D, no special glasses required (though Internet is).
STEREO, which stands for Solar Terrestrial Relations Observatory, consists of two spacecraft (also called probes) that NASA sent up from Earth in 2006. Now, “The duo are on diametrically opposite sides of the sun, 180 degrees apart,” according to the agency’s website. “One is ahead of Earth in its orbit, the other trailing behind.” Each probe keeps tabs on its part of the solar pie, photographing half of it and sending the images back to earth. Then, researchers combine those shots to make a sphere (see a video of a composite, rotating sun here). It's the first time in human history that we've had a view of the entire sun. "These aren't just regular pictures,” Dr. Tony Phillips of NASA's Heliophysics News Team wrote this past February. STEREO’S telescopes are tuned so that they can “trace key aspects of solar activity such as flares, tsunamis and magnetic filaments. Nothing escapes their attention.”
In the past, for example, an active sunspot could appear on the side of the sun hidden from us on Earth. “Then, the sun's rotation could turn that region toward our planet, spitting flares and clouds of plasma, with little warning,” Phillips noted. Not anymore. Scientists can whiz to the other side to see what’s brewing.
So why should the rest of us grounded folk care about what’s going on 93 million miles away? We increasingly rely on technology that’s vulnerable to space weather, according to NASA’s website. (Space weather happens when a solar storm—either a coronal mass ejection or a solar flare—from the Sun travels through space and impacts the Earth’s magnetosphere). “NOAA is already using 3D STEREO models of CMEs (billion-ton clouds of plasma ejected by the sun) to improve space weather forecasts for airlines, power companies, satellite operators, and other customers," Phillips wrote. "The full sun view should improve those forecasts even more.”