Guest guest Posted October 28, 2003 Report Share Posted October 28, 2003 Sun shoots monster flare at Earth "The flare today may be the third strongest X-flare on record," The latest in a series of eruptions is the biggest to head our way since '89; power grids, satellites brace for the blast The bright spot near the center of this false-color ultraviolet image of the sun, captured by the Solar and Heliospheric Observatory on Tuesday, represents a huge flare heading toward Earth. By Robert Roy Britt SPACE.COM Oct. 28 — The sun on Tuesday unleashed what appears to be the third most powerful flare in recorded history, a storm of charged particles that could hit Earth midday Wednesday with more effect than any since 1989, when power was knocked out to an entire Canadian province. DEPENDING ON the storm's magnetic orientation, it could set off a dramatic display of colorful northern lights well into midlatitudes of the United States and Europe. Meanwhile, satellite operators and power grid managers are preparing to endure a potentially damaging event. And astronauts aboard the international space station have taken cover from heavier radiation sent out by the flare. They are not expected to be in any serious danger. Kicked up at 6 a.m. ET Tuesday, the major solar eruption comes on the heels of four other flares late last week and over the weekend. All were considered fairly severe, but the latest eruption makes the others seem like solar sneezes. Tuesday's eruption is classified as an X18, where X denotes a major flare and larger numbers are stronger. That compares to two flare-ups over the weekend that were rated less than X2. "The flare today may be the third strongest X-flare on record," said Paal Brekke, the European Space Agency's deputy project scientist for the Solar and Heliospheric Observatory, which first spotted the event. A slightly stronger flare on April 2, 2001 was not pointed at Earth. Tuesday's storm is headed directly at us and could generate fantastic colorful lights in the atmosphere, known as auroras. The storm associated with the flare is called a coronal mass ejection, an expanding bubble of charged particles that race outward. COMING FAST The storm is traveling quicker than most and is forecast to arrive about 30 hours after it left the sun, Joe Kunches, lead forecaster at the National Oceanic and Atmospheric Administration's Space Environment Center, said in a telephone interview. That would put the arrival at about noon ET Wednesday. "That's when it starts," Kunches said. But the storm will blow through over several hours, he said, and won't be done for up to two days. "We may be in for some great aurora," Brekke said. Auroras are created when the charged solar particles stream down Earth's magnetic field lines and excite oxygen and nitrogen atoms in the atmosphere. Normally, the auroras are only visible from place near the poles, like Alaska. But when Earth's magnetic field is overwhelmed, auroras can become visible well into the United States and Europe. For U.S. residents, Wednesday evening could provide the best chance to see auroras. POTENTIAL THREAT The storm is also potentially a serious threat to satellites and other communication systems, including power grids on Earth. Kunches said satellite operators and power grid managers are likely to take stringent measures to protect their assets. Engineers can put some satellites into hibernation modes, and power grid operators arrange for less switching and fewer large-scale power swaps. Nobody can say in advance what will happen, though, because the result depends on the orientation of Earth's magnetic field in relation to that of the storm. "Until we know the orientation of the magnetic field in this [storm] cloud we won't know how severe the geomagnetic storm will be," Brekke said. "If the cloud has a southward-directed magnetic field it will be severe, while if it has a northward component it will not affect us that much." --- ----------- Understanding space storms Space storms occur when the sun throws off an outburst of radiation and energetic particles that can interact with Earth's magnetic field. Such storms can disrupt communications, damage satellites and even pose health risks. The National Oceanic and Atmospheric Administration has set up three scales to measure the severity of "space weather." Click on a category above to see what effects each level of space storm can create: G5: Extreme. Collapse of power grid systems, damage to transformers, satellite link problems, radio disruption. G4: Severe. Potential problems with stability of power grids, satellite corrections needed, radio communications affected. G3: Strong. Voltage corrections required, false alarms triggered on protection devices, satellite problems, intermittent radio problems. G2: Moderate. High-latitude power systems affected, possible effect on satellite orbits, fading in high-frequency radio signals at high latitudes. G1: Minor. Weak power grid fluctuations, minor impact on satellite operations, migratory animals begin to be affected. S5: Extreme. High radiation hazard for spacewalkers. Passengers in high-flying aircraft at high latitudes may receive radiation dose equivalent to chest X-ray. Some satellites lost. No high-frequency communications possible in polar regions. S4: Severe. Radiation hazard for spacewalkers. Satellites encounter problems. Some blackouts in high-frequency communications in polar regions. S3: Strong. Spacewalkers should take measures to avoid radiation hazard. Single-event satellite upsets. Degraded high-frequency communications in polar regions. S2: Moderate. No biological impact. Infrequent single-event satellite upsets. Small effects on high-frequency communications. S1: Minor. No biological impact. No impact on satellite operations. Minor impact on high-frequency radio in polar regions. R5: Extreme. Complete high-frequency radio blackout on Earth's sunlit side for several hours. Low-frequency outages. Increased navigation errors. R4: Severe. High-frequency radio blackout for one or two hours, affecting most of Earth's sunlit side. Low-frequency outages. Minor disruptions in satellite navigation systems. R3: Strong. Wide-area blackout of high-frequency radio on sunlit side. Low-frequency signals degraded for about an hour, affecting navigation systems. R2: Moderate. Limited blackouts of high-frequency radio on sunlit side. Low-frequency navigation signals degraded for tens of minutes. R1: Minor. Minor degradation of high-frequency radio on sunlit side. Low-frequency navigation signals degraded for brief intervals. Printable version --- ----------- The space storm is intrinsically stronger than one on March 6, 1989, that tripped a power grid in Quebec, Canada. The greatest solar storm on record occurred in 1859, shorting out telegraph wires and starting fires in the United States and Europe. Brekke told Space.com that the oncoming storm, if it hooks up with Earth in just the right way, would be about one-third as strong as the 1859 tempest. It could, he added, be either less or more powerful than the 1989 storm. The coronal mass ejection is one in a series sent out by two huge sunspots, the largest pair to grace the sun at one time in recent memory. ASTRONAUTS TAKE COVER Tuesday's eruption also accelerated a high-energy proton shower. These can cause damage to satellites and can be harmful for astronauts, Brekke said. NASA is careful not to plan spacewalks during solar storms. March 9, 1999 — Twisted magnetic fields on the sun spawn violent explosions that can affect Earth. Montana State University physicist Richard Canfield explains the process, using a dramatic NASA animation. Aboard the international space station, the Expedition 8 crew of Mike Foale and Alexander Kaleri adjusted their workday a bit in response to the storm. Radiation from a solar flare — which preceded the coronal mass ejection — arrives at light-speed and was detected at the orbiting outpost. Light and other radiation travels from the sun to Earth in about 8 minutes. Beginning at 8:49 a.m. ET Tuesday and continuing through 1:45 p.m. ET, the two-man caretaker crew confined themselves to the most heavily protected area of the station for about 20 minutes during every 90-minute orbit. The specific times, all in ET, are 9:35 to 9:55 a.m., 10:20 to 10:45 a.m., 11:50 a.m. to 12:15 p.m. and 1:25 to 1:45 p.m. The times coincide with when the station's orbit takes it to the farthest north and south points from the equator, areas where Earth's magnetic fields provide the least amount of natural protection from the sun's fury. "The crew has seen some higher levels of radiation, so that's exactly why they do this," NASA spokesman Kyle Herring said. "The flight surgeons monitor this very, very closely." Increased solar activity also prompted the Expedition 2 and Expedition 3 crews to take similar precautions in April and November 2001, respectively. The safest part of the station is the far end of the Russian Zvezda service module. The Soyuz spacecraft — one of which returned to Earth last night with the crew of Expedition 7 — is not as safe as many people think, even though it has a heat shield, Herring said. The Soyuz craft that brought Foale and Kaleri into space remains docked to the station as an emergency lifeboat. "The Soyuz offers probably the least amount of protection," Herring said. Jim Banke, senior producer at Space.com's Cape Canaveral Bureau, contributed to this report. © 2003 Space.com. All rights reserved. Quote Link to comment Share on other sites More sharing options...
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