| Earth buffeted by big solar storm | |
| OooOo | Earth buffeted by big solar storm
[img]http://i.cnn.net/cnn/2003/TECH/space/10/29/solar.storm/story.solar.flare.nasa.jpg[/img]
The Solar and Heliospheric Observatory satellite spies the third most powerful solar flare on record, the bright blip near the sun's middle.
(CNN) -- A big electrified gas cloud hurled by one of the largest solar flares on record began hitting Earth early Wednesday, triggering a major geomagnetic storm that has the ability to affect satellite radio communications and Earth-based electrical systems. The fast-moving shock wave buffeted our planet at about 1 a.m. EST, much soon than expected. It arrived about 19 hours after the third largest solar flare on record erupted on the sun, according to Paal Brekke, a project scientist with the Solar and Heliospheric Observatory (SOHO), a sun-watching satellite mission jointly run by NASA and the European Space Agency. Solar scientists expect strong to severe geomagnetic storm conditions to persist throughout the day, abating early Thursday. Tuesday's flare outburst was classified an X17.2 flare, according Brekke. In comparison, two solar storms observed last week were between X1 and X5. Flares also are often associated with coronal mass ejections, or CMEs, like the one that arrived Wednesday morning. Usually CMEs need several days to make the 93 million mile trip, but this one was one the fastest ever. So far, no major problems have been reported. Yet one Japanese satellite went out of commission this weekend, possibly due to electrical problems associated with increased solar acivity. And instruments onboard the SOHO orbiter have been turned off during the storm to prevent malfunctions. The high-energy solar winds produced by a CME can generate geomagnetic storms when they interact with Earth's magnetic field -- often increasing displays of the northern and southern lights. Because this CME is hitting Earth directly, it is possible that the geomagnetic activity will disrupt satellite communications or power grids. In recent years, however, satellite and utility operators have devised safeguards that usually prevent or minimize damage from solar storms. NASA has taken precautions as well with its most precious cargo, astronaut Mike Foale and Russian cosmonaut Alexander Kaleri on board the International Space Station. Foale and Kaleri, the only humans currently outside the protection of the Earth's atmosphere, are retreating during peak exposure times to the living quarters of the station, which provides the best radiation protection. As a precaution, NASA shut down the station's robotic arm, which is the most exposed piece of hardware. Researchers classify solar flares using three categories: C for weak, M for Moderate and X for strong. The largest flare on record, one of two known X20s, occurred on April 2, 2001. However, it was not directed at the Earth. Space weather forecasters say this spate of strong solar flares is unusual because it is not following normal patterns of solar behavior. The sun follows an 11-year cycle of activity, and the last peak took place in 2000. prevzemeno od http://www.cnn.com/2003/TECH/space/10/29/solar.storm/index.html |