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Right now, forecasters rely primarily on SOHO for early warning about CMEs. UNH scientists worked on one of the key instruments on SOHO, which was launched by the European Space Administration in 1995. The satellite monitors the sun and beams a continuous stream of images to researchers on Earth. Those chronographs can show a CME in progress two- to four-days before the blast of plasma gets here.

SPACE WEATHER ON THE WEB

If you wonder what kind of space weather is in store for your planet today, go to NOAA's Soace Environment Center website [www.sel.noaa.gov] for the latest forcast. You can find out if any geomagnetic storms, radiation storms, or radio blackouts are brewing, check on solar wind conditions, and take a look at images of the sun itself. For more space weather information and a fabulous gallery of photos of all kinds of astronomical phemonena, visit www.spaceweather.com . You'll also find real-time images of the sun and another great photo gallery at NASA's web page for the Solar and Heliospheric Observation [SOHO] at http://soho.esac.esa.int/ .

"But even when we know a CME is coming, we still don't know whether it will be geo-effective," Galvin says. "Will it actually cause a magnetic storm when it reaches Earth? And if it does, how big a storm will it be? Sometimes an event that comes off the sun seems minor--not dramatic at all, visually--but when it reaches Earth, it has a big effect."

Both SOHO and another satellite equipped with a UNH-built instrument, the Advanced Composition Explorer (ACE), can actually sample and analyze the solar wind to collect more detailed information about what's coming our way. But by the time they're able to do that, whatever is coming is almost here. "Basically, by the time we know whether it's going to affect us or not, we have only about a one-hour warning," Galvin observes. "What we're trying to do with STEREO is to get a better correlation between the in situ measurements of the solar wind and the remote observations of the sun, so we'll have a better idea of which solar events will have an effect on Earth."

Galvin's goal is not just to become a better space-weather forecaster, but to gain a deeper understanding of how the sun works. "We know there's an 11-year sunspot cycle. We know this has something to do with the fact that the sun spins faster at the equator than it does at the poles. This twists up magnetic field lines, and we know that sunspots and coronal mass ejections and flares are ways of releasing this pent-up magnetic energy. But we don't understand why the cycle is 11 years. We don't know how to predict whether this cycle will be more intense than the last, or when the next big event is going to happen. We don't understand these things, so we need more in-depth information about how and why the sun does what it does."

Galvin glances at the computer monitor on her desk, which displays a real-time image of the sun as seen by SOHO. "When I think about the sun, I don't envision the big yellow ball that we see out the window," she says. "I always think of these extreme ultraviolet images. Looking at them, you can see that even when the sun is quiet, it's percolating, churning. It's keeping busy, and it's just fascinating to look at." ~

Writer Jake Chapline is a frequent contributor to this magazine.

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