How NASA Is Preparing for the Next Solar Flare
A huge solar flare erupted from the Sun yesterday, but it won’t have much effect on the Earth. The dreaded “coronal mass ejection” (CME), the chunk of matter that bursts from the sun itself, won’t come near the planet. If it did, the Earth wouldn’t get much of a warning, but NASA is working on a new method to better track and predict damage from solar flares.
Yesterday’s solar eruption was a Class-X flare, the most powerful kind. Fortunately, it was directed away from the Earth, so there’s very little chance it will cause any damage to man-made objects in orbit. It’s just the latest event in period of high activity from the Sun, says NASA.
“The sun is doing a scattershot,” says Micheal Hesse, chief of NASA’s Space Weather Laboratory at the Goddard Space Flight Center in Maryland. “It’s been shooting out some pretty fast CMEs in all sorts of directions, and so far very few of them have really gone our way. Sooner or later, the sun will get it right, and we’ll have a little excitement here.”
That “excitement” could amount to damaged satellites and disrupted communications. Solar flares produce intense bursts of radiation that can knock out equipment in orbit. On top of that, a large enough CME can wreak havoc with man-made equipment in space, and be extremely dangerous to astronauts.
Since the flare shot out of the Sun at an angle, it was more easily observable. Hesse notes that sometimes large flares that are directed at the Earth are harder to measure, since the path of the flare isn’t as obvious head-on. At the same time, the CME is difficult to track; in most flares, instruments can detect the initial ejection as well as its size and shape when it gets close to Earth, but can’t track how it propagates.
That’s changing, however. NASA is planning to use a pair of satellites to track the CMEs from future flares. Called the STEREO spacecraft (short for Solar Terrestrial Relations Observatory), they’re positioned in such a way that the movement of anything between the Sun toward the Earth is directly observable. With STEREO’s heliospheric imagers, NASA will finally be able to track CMEs in (almost) real time.
“Imagine if someone starts rolling a bowling ball,” says Hesse. “But the ball isn’t running on a smooth surface—it has spots that could slow it down or deflect it a bit. Imagine you’re watching the person rolling the ball, then you close your eyes and predict the impact. What this does is open your eyes.”
Since the CME is literally a chunk of the Sun, it’s not as predictable as a simple wave—more like a cloud of smoke that’s expanding and shifting as it moves through space, except this cloud can be deadly to satellites. By tracking how it propagates through space toward the Earth, space scientists will have a better idea of how much damage it might cause.
“For a CME, it’ll give you lead time [when the flare occurs], but you won’t know what happens in the interim. You only see it when it actually gets to the earth. The new data will actually let us see this thing propagate. It’s like when you’re tracking a hurricane, you get almost hourly updates. That’s the kind of thing we want to do.”
NASA should have plenty of chances to try its new tracking technique. Although the current 11-year solar cycle is less powerful than previous ones, its “tide” is still rising, with the expected peak coming in 2013. There will likely be many powerful solar flares before then. Yesterday’s was a prime example, and was also notable for having a relatviely tiny CME.
“The flare was one of the biggest we’ve had this solar cycle,” Hesse says. “The CME wasn’t particularly impressive. You can get a big CME without hardly a flare at all, or a big flare with hardly a CME, or you can get both. Part of the problem, and that’s why NASA is spending so much time investigating this, is we don’t understand this connection compeletely. And we need to.”