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Sun storms may zap Earth's electric power systems

Source: Bangor Daily News Bangor, ME Publication date: Mar 09, 2000

On March 13, 1989, writes Robert Zimmerman in last August's issue of Star Date, a massive power grid that supplied electricity to over 6 million residents of Quebec suddenly crashed. Nor were the problems confined to Quebec as about 200 U.S. utility companies experienced similar, although less severe, equipment failures.

At the same time, a New Jersey nuclear facility had three transformers explode that cost $8 million to replace while high above Earth the GOES-7 satellite burned out half its solar cells, cutting its effective service life by half. What was going on?

The disruptions were not due to some James Bond-like attack by terrorists but the sun undergoing a gigantic eruption called a coronal mass ejection. It caused huge amounts of charged particles and energy to crash into the earth, overwhelming electric grids and related equipment.

The sun's activity peaks on a roughly 11-year cycle, and the next expected peak comes this year. Many solar experts are warning that the results could prove disastrous for everything from satellites to wireless telephones. That solar storms can affect Earth's electrical power systems should come as no surprise, says Sten Odenwald in the March 2000 issue of Sky & Telescope.

In the 1800s, solar storms sometimes induced sufficient current in telegraph lines that messages could be sent without the use of batteries. In fact, writes Odenwald, this is the crux of the problem; the nation's electrical grid makes an excellent conductor for the currents produced by solar storms. But the storms produce direct current while the electric grid is designed to operate off alternating current. The surge of DC current causes transformers to heat up and fail if safety switches do not shut down the system. The Quebec shutdown was a case of the system protecting itself while the spectacular explosion of a 230,000-volt transformer in British Columbia was an instance of the safety system not reacting in time. Circuitry in satellites and other space vehicles is also at risk from the energy of solar storms. Odenwald mentions the $200 million Telstar satellite that had a massive power failure in 1997 and the 1998 loss of a PanAmSat Galaxy 4 satellite that temporarily shut down service to 45 million wireless pagers in North America. Causing the present concern is not the fact that the sun's behavior is any different today from what it always has been but that more electronics exist to be affected by it. During the last peak cycle in 1989-90, there were only 102 operating satellites and the United States had 3 million wireless phone users. Today there are over 1,000 satellites, with three- quarters of these in the $80 billion communications market, and around 50 million wireless phone users. These numbers, combined with the interconnecting electrical gridwork covering North America, could be a disaster waiting to happen if a particularly powerful storm were to strike.

NASA also has its concerns as work on the International Space Station picks up. An astronaut's career radiation dose is 400 rem, a figure roughly equal to 20,000 chest X-rays. Being caught outside the space station as the aftermath of a solar storm passes by could expose astronauts to so much radiation that their careers would be at an end.

So what is a solar storm? In 1826, German astronomer Heinrich Schwabe began what was to become a 43-year study of the sun's surface. Over the years he found that the number of sunspots, dark areas moving across the face of the sun, appeared to peak every 11 years. These spots, often far larger than Earth's diameter, are dark because they are cooler than surrounding areas of the sun. They are indicative of complex electromagnetic interactions taking place in the interior of the sun, and are still not fully understood, but it is known that these interactions can give rise to a veritable zoo of solar phenomena including flares, prominences, sunspots, coronal holes and coronal mass ejections, or CMEs.

Of these by far the most important, from Earth's perspective, are the CMEs. During a CME, billions of tons of matter and energy are spewed from the sun at speeds of several million miles per hour. When this reaches Earth about four days later, it often interacts with the planet's magnetic field to produce the spectacular celestial shows called aurorae or northern and southern lights.

But, says Ron Zwicki of the Space Environmental Center, "all hell breaks loose," with the nation's power, communications and guidance systems. As with hurricanes, nothing can be done to prevent solar storms from striking, but steps can be taken to lessen their impact if there is sufficient warning.

According to Gary Taubes, writing in a recent issue of Science, two spacecraft are in orbit that will help with the predicition of "space weather." SOHO monitors activity at the sun's surface while ACE keeps an eye on the solar wind, i.e., the rapidly moving cloud of charged particles heading Earthward after a CME. Other satellites are in the planning stage but, as Goddard Space Flight Center's Jim Green recently remarked at a solar research conference, "Our ability to forecast solar events remains no better than 50-50. We could do as well flipping a coin." Which means that power companies and owners of communication satellites can only hold their breath and see what damage this latest cycle of solar activity will cause.

Clair Wood taught physics and chemistry for more than a decade at Eastern Maine Technical College in Bangor.

Publication date: Mar 09, 2000 ) 2000, NewsReal, Inc.

-- Carl Jenkins (, March 10, 2000

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