It's always stormy weather
AIR FORCE SPACE COMMAND NEWS RELEASE
Posted: April 16, 2003

"The weather forecast for tomorrow is increased solar winds with heavy electromagnetic radiation. So be prepared to protect yourself from more-than-usual doses of X-rays coming your way."

Evening news watchers would likely be baffled by such announcements. They want to know about rain, snow or sunshine in their neighborhood. But the effects of solar winds, flares and electromagnetic radiation is becoming more apparent with every day mankind spends in space.

"Space is not a vacuum and it's not benign," said Capt. Christian Wohlwend, chief of space environmental operations at Headquarters Air Force Space Command. "We're finding out that it's the hardest environment to operate in."

The source of all this turbulence is also the source of life on Earth -- the sun.

The star that is the center of our solar system can erupt with furious bursts of exploding energy called solar flares.

Solar flares, enormous explosions of hydrogen and helium above the sun's surface, are the largest explosions in the solar system. A typical one can release the equivalent of millions of 100-megaton hydrogen bombs exploding at once.

These flares emit waves of electromagnetic radiation and low- to high-energy particles and are carried through space by solar winds attracted to its neighbors along interplanetary magnetic fields. Earth gets its fair share of these solar storms but our own magnetic shield, called the magnetosphere, and our upper atmosphere, the ionosphere, absorbs much of the harmful effects. Without them, Earth dwellers would fry faster than chicken in Kentucky the day before the Fourth of July. As it is, the third planet from the sun is blissfully unaware of the turmoil cooking up in that gaseous orb 150 million kilometers away. But that doesn't mean we don't feel the effects.

According to Lt. Col. Michael Bedard, chief of aerospace weather at Headquarters Air Force Space Command, these waves of electromagnetic radiation and particles can play havoc with technologies venturing out of that safety cocoon into space. And sometimes, the storms are so powerful, they can punch their way into our daily lives, whether we are ready or not.

"There are solar cycles of violent solar flares about every 11 years," he said. "In 1989, about 6 million people in Quebec lost electricity after energy particles from a solar flare hit the north-south power lines, along the longitudinal magnetic field lines. It caused an overload. Transformers blew everywhere."

If going without your toaster for a day causes you to shake uncontrollably, imagine a soldier using Global Positioning System readings to mark a minefield. Energized particles from solar events can cause a single frequency receiver to "lose lock" with the GPS satellite. Stepping on a mine you thought was 10 feet in the other direction can cause irreparable harm to your sunny disposition.

When low- to medium-energy particles pummel the Earth, in what's called "geomagnetic storm events," they can cause interference to any ground-based radar, as well as create space tracking and launch trajectory errors.

High-energy particles, like its low- and medium-energy cousins, are just specks smaller than dust. But it can slap a satellite hard enough to penetrate its protective casing. Two satellites, one European and another Canadian, were turned into scrap metal in the early Œ90s after a solar flare eruption. It takes as little as 15 minutes for these particles to travel to Earth in what scientists call "proton events."

"One proton can be enough to kill a satellite," said Wohlwend. "Commercial satellite makers don't feel they need to protect their machines against a nuclear strike and circuitry gets smaller and smaller. The smaller the circuit, the bigger the problem when a proton hits it."

Particles aside, space weather watchers still have to worry about electromagnetic radiation, which reaches the Earth with all the immediacy of bad news. This radiation carries X-rays, extreme ultra-violet waves and radio waves. Scientists are still studying the effects of prolonged exposure to X-rays for astronauts and U-2 pilots. But, for most of us common folk who don't travel to those extremes, this radiation can cause satellite communication and radar interference along with ground-based short wave radio signal fades.

So if you feel like making a call home to thank Mom for keeping you indoors for piano lessons while the other kids were playing outside during summer, solar flares could interfere with that call. The ionosphere thickens when hit with electromagnetic radiation. The more radiation, the thicker it gets. A thick ionosphere means it's lower to the surface. High-frequency signals bounce off the ionosphere to get to another receiver. The lower the ionosphere, the less distance. At night when the ionosphere cools off, it gets thinner and higher, which explains why you're able to get Barvarian radio at night but only that lousy easy-listening station in town at noon.

"Space weather has important potential impact on both military and civilian operations," said Bedard. "People should be more aware. There are navigational and communications aspects as well as power production concerns. It's this knowledge that allows the engineer to design protection for space systems, which we have done. There is now a dual-frequency GPS to avoid the problems of the single-frequency GPS receiver. And we've hardened our satellites in space, too."

The Air Force has six solar observatories -- in Italy, Australia, Puerto Rico, Massachusetts, New Mexico and Hawaii. That data is used by two customers -- the National Oceanic and Atmospheric Administration's Space Environment Center in Boulder, Colo., and by the Air Force Weather Agency at Offutt AFB, Neb. The Air Force facility sends out warnings and alerts to Department of Defense assets about solar flares.

Which is not to say we are any closer to long-term predicting.

"We have limited forecasting," Wohlwend said. "We're only beginning to see patterns of recognition that could potentially impact the Earth."

Bedard is more blunt.

"Space weather is in its infancy," he said. "We're about at the spot in space weather that we were in the 1940s in meteorology. We just have a lack of data."




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