The sun is emerging from its latest peak activity cycle having inflicted some damage on our technologically fragile civilization but also providing new insights into what drives the phenomenon, scientists told United Press International.
"Solar max," as it is popularly known, is the regular peak of the sun's energy output. About every 11 years, the star's nuclear furnace reaches a sort of zenith, generating several changes in its appearance and effects. Scientists have been observing solar activity for hundreds of years. Sunspot records go back to the observations of Galileo's improved telescope in 1610 and provide a nearly continuous record since then.
The latest solar max was a "double peak maxima," David Hathaway, solar physics group leader at NASA's Marshall Space Flight Center in Huntsville, Ala., told UPI. "The first peak was in April of 2000 and the second in November or December of 2001," Hathaway said. "The second peak wasn't as big as the first one."
The total duration of Solar Max 2000 was roughly three years, and is it only coming to a close now. There were no power failures as dramatic as those in 1989, but several satellites have been damaged or completely disabled and the electric power system in the northeastern United States was stressed -- though it did not fail.
Solar max refers to a period when the number of sunspots -- dark islands of relatively cool gases on the sun's surface -- reaches its maximum. The star generates huge emissions of gas and electromagnetic waves, called solar flares, and the solar wind -- streams of high-energy particles radiating in all directions -- reaches high levels of intensity. There also are "solar mass ejections" -- slower moving but massive eruptions of solar material into space.
All of this activity has direct and measurable impacts on Earth and, especially, on satellites in space. In 1989, a solar storm blew voltage regulator on the Hydro-Quebec Power Grid in Canada. Within 2 minutes, a cascade of broken circuits reached across the province, causing a power blackout that cost Hydro-Quebec at least $10 million and last several days for thousands of electricity customers.
During World War II, a solar max temporarily knocked out all high-frequency radio traffic in England.
Joe Allen, scientific secretary of Scientific Committee on Solar-Terrestrial Physics, said, "There have been several satellite failures and some pretty spectacular ones."
Allen told UPI on July 14, 2000 -- Bastille Day in France -- there was a big solar flare followed by a cloud of particles ballooning out from the sun in a coronal mass ejection.
"The really high speed particles arrived on Earth within minutes," he said, but the solar material traveled more slowly. "It upset satellites, caused problems with electrical power lines. All the variety of things that can happen did happen. It was not as spectacular as the March 1989 sequence, but it was the biggest thing to happen in this solar cycle."
Allen said in April 2001 in New England, during another large solar storm, power lines were affected and "there was a straining on transformers. Nothing burned out that time, that I know of," he said, "but the mean time between failures on transformers is shorter than on transformers that have led a more placid life. April 2001 in particular affected ground-based equipment. Not many people know about it, but it is generating some interest."
Peter C. Klanowski, a freelance writer in Germany who maintains a Web site dedicated to satellite failures, found 12 satellites failing in 2000, 23 in 2001, and eight so far in 2002.
"In my personal opinion," he wrote on the Web site, "there are quite likely many more partial satellite failures than those listed here. Not every satellite operator is required to disclose important facts that may affect business. Many partial failures actually don't affect business at all. Satellite operators with sufficient backup capacity could even conceal a total failure of one of their satellites. They proved that already."
Satellite problems have included "hits" on deep space orbiters, degradation of solar panels, navigation interference, electrical arcing across circuits and communication difficulties. However, it is often difficult to pin down whether a particular problem was caused by solar max or some other malfunction.
One satellite failure indisputably the result of solar max occurred on July 15, 2000 during the Bastille Day coronal mass ejection. Japan's Advanced Satellite for Cosmology and Astrophysics went into safe mode that day. The satellite lost attitude. Power levels dropped to a critical level because the solar arrays no longer were properly aligned toward the sun.
ASCA's problems apparently developed from a chain reaction of events. Solar activity increased atmospheric drag. The drag began to spin the satellite about one revolution every 3 minutes. Control could not be restored.
"We regret that we must announce that the possibility that ASCA will return to observation mode is very small, almost hopeless," ASCA officials announced in a news release. "The battery cells may have suffered serious unrecoverable damage."
Chris Kunstadter, of U.S. Aviation Underwriters Inc. of New York City, a major satellite insurer, said, "Space weather has been suggested as a cause or contributor to over $500 million in insurance claims in the past five years ... There have been roughly a half billion dollars worth of insured satellite losses where solar activity may have been a contributing factor." And only about 20 percent of all satellites are insured.
NASA's Hathaway said the data are only beginning to be analyzed but a few preliminary surprises are in.
"As far as predicting the maximum -- how big it would be before it started -- it surprised us," Hathaway said. "Predicting a maximum size is a cottage industry. There are hundreds or thousands of people who do it. Given that, some people are going to get it right. We're looking at how reliable those techniques ought to be. Only three or four are very reliable."
Improved scientific prediction of solar maximum may become increasingly important in the future as humans extend their reach into space. "Most of the effects are felt in space," Hathaway said. "Astronauts can have problems since the radiation environment even in low earth orbit can get dangerous."
He added NASA will have to keep track of radiation levels, especially with extra-vehicular activities. "If and when we go beyond low Earth orbit -- to Mars or beyond -- outside the magnetosphere, astronauts can get lethal doses. Solar max is of increasing concern with humans in space."