A significant blast of energy from the sun arrived at Earth Tuesday at 10 a.m. EST, triggering a moderate geomagnetic storm here that's unlikely to cause major problems. But skywatchers take note: the storm could set off bright Northern and Southern lights Tuesday night, possibly visible from as far south as New York and Oregon.
Forecasters and scientists with NOAA's Space Weather Prediction Center (SWPC), the nation's official source of warnings and alerts about space weather and its impacts on Earth, observed an explosion from the sun's outer atmosphere Sunday evening. That "coronal mass ejection" streamed toward Earth at more than 4 million miles an hour.
"When these coronal mass ejections hit Earth's own magnetic field, they energize the Earth's magnetic field and cause it to fluctuate," said SWPC physicist Doug Biesecker, Ph.D. During a moderate or strong storm, such fluctuations can temporarily impair navigation, power, satellite and other systems.
When such events are directed toward Earth, power grid managers and other systems operators keep an especially close eye on SWPC forecasts. If a storm is imminent, satellite operators can switch into standby mode and temporarily forgo communication between ground control and spacecraft in orbit to prevent the garbling of messages. Airlines can reroute planes that normally take fuel-saving polar routes. Along those routes, pilots depend on high-frequency (HF) radio communications that are vulnerable to disruptions by space weather.
Major disruptions are unlikely with a storm the size of the one that arrived Tuesday morning. One day earlier, however, on Monday, Jan. 23, airlines rerouted airplanes away from the poles. Radio communications were hampered by the strong radiation storm that began on Monday and continues today. SWPC has also received reports of "soft" or correctable errors on satellite systems that are associated with the solar radiation storm.
Teams of forecasters staff SWPC's operations center 24 hours a day, seven days a week, watching monitors intently for space weather "fronts" heading toward Earth. The forecasters rely on data from a network of monitors, including NOAA and NASA satellites, and U.S. Geological Survey sensors that detect disturbances in Earth's magnetic field (magnetometers).
At NOAA's Satellite Operations Facility in Suitland, Md., experts control the spacecraft that closely monitor solar activity and process the data that go into the SWPC forecasts. The SWPC issues space weather alerts, noting triggers that are important to different users. SWPC forecasters speak daily with NASA, for example, since astronauts in low Earth orbit could receive an extra dose of radiation when energized particles sweep by.
The sun goes through phases of high and low activity, in a cycle of about 11 years. The sun's activity is currently increasing, with the next solar maximum expected in May 2013.
Tuesday night (Jan. 24) could also bring aurora to parts of Europe, Asia and North America. For an experimental auororal forecast, which is updated regularly, see: http://helios.swpc.noaa.gov/ovation.
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