May 12, 2000. Copyright 2000. Graphic News. All rights reserved.

MAGNETIC STORMS ARE BLOWINÕ IN THE WIND

LONDON, May 12, Graphic News: POWER COMPANIES in northern Europe, the U.S. and Canada are bracing for the possibility that a solar storm could knock out generating and transmission systems when the sun reaches the height of its 11-year sunspot cycle this summer.

In the worst recent geomagnetic storm caused by Òspace weather,Ó a solar tempest plunged the Canadian province of Quebec into a blackout in March 1989, leaving six million people without electricity for nine hours and nearly toppling the power grid in the U.S. Northeast.

In January 1994, a multimillion-volt solar storm knocked out CanadaÕs main television broadcast satellite, Anik-E2 and a similar storm in 1997 is believed to have caused the failure of a $200 million Galaxy-4 communications satellite.

The sun may be 93 million miles (150 million km) away, but this ball of hydrogen and helium at the centre of our planetary system is a massive nuclear reactor, spewing out high-energy electrically charged atomic particles known as the solar wind. At the height of its 11-year cycle the sun can spawn monster explosions known as coronal mass ejections Ð massive blasts triggered by sun spots, solar flares and tortured loops of super-heated X-rays in the sunÕs magnetic field. These bursts heat material to millions of degrees in just seconds and blast billions of tons of material into space.

As these charged particles smash into EarthÕs magnetosphere, the magnetic bubble that surrounds and protects the planet, some break through causing geomagnetic storms, bright auroras, damage to satellites in Earth orbit and disruption of power by generating strong electric currents under the EarthÕs surface.

This increased solar emission also causes the earthÕs atmosphere to expand, creating increased drag on orbiting satellites. This can cause satellite orbits to decay more rapidly than predicted.

Astronauts aboard Skylab were the first to witness solar flares and coronal mass ejections, recording 160,000 images in nine months. Launched in 1973, the space station was supposed to remain in orbit until the 1980s Ð ironically, due to increased solar activity the 100-ton craft re-entered earthÕs atmosphere in 1979 Ð raining debris over the Indian Ocean and parts of Western Australia. The current rise in solar activity has had the same effect on the fledgling International Space Station, requiring a re-scheduled Shuttle mission to boost it to a higher orbit.

Unable to predict reliably when and where a coronal mass ejection will occur, space meteorologists at best have only been able to make a 50-50 guess about when violent space weather is on its way. But now NASAÕs Advanced Composition Explorer (ACE) spacecraft, orbiting a million miles (1.6 million km) from Earth, has a magnetometer and a particle detector aboard that can warn of solar bursts about 45 minutes before they reach the atmosphere Ð sufficient for satellite operators to protect sensitive systems.

Researchers gathering data using the joint European-U.S. telescope satellite, SOHO (Solar and Heliospheric Observatory), JapanÕs Yohkoh (ÒsunbeamÓ) and the TRACE (Transition Region and Coronal Explorer) satellites have answered many questions about the dynamic character of the sunÕs corona but two enduring mysteries remain.

The first concerns the way in which sound waves reverberate through the sun, causing the surface to swell up and down by 30 miles (50 kilometres) every five minutes or so. By monitoring the way these patterns change Ð famously described as the sun singing to itself Ð we could learn more about the sunÕs 11-year sunspot cycle. And the second is the fact that within 300 miles (500 kilometres) above the sunÕs surface, its temperature rises from 8,000 degrees Celsius to half a million (14,000 to 900,000 degrees Fahrenheit). In other words, the sun appears hotter on its outside than on its surface, which seems to defy the laws of science.

Recently SOHO has confirmed that oxygen particles in the solar wind are heated to about 200 million degrees Celsius (360 million degrees Fahrenheit), hotter than any temperature previously measured in the outer corona, and accelerated to more than 500,000 mph (800,000 km/h).

The effects of space weather reach far beyond Earth. Gigantic dust devils rage on Mars, Jupiter is a world racked by atmospheric violence and even the distant planets are battered by the sunÕs evaporating atmosphere.

Space weather not only creates spectacular auroras Ð Òthe souls of dead soldiers fightingÓ as they are known in Norway Ð but can wreak havoc as its impact on Earth becomes more critical.

/ENDS

Sources: NASA/Marshall Space Flight Center; Cambridge Atlas of Astronomy; The Planets, BBC; Associated Press; Reuters