Perfect Sun Storm Threatens Power, Phones

James Owen in England
for National Geographic News
October 29, 2003
One of the largest solar eruptions in history is sending a giant electromagnetic pulse our way at speeds of millions of miles per hour. Due to hit Earth any time from now, scientists say it could trigger worldwide outages in power grids and communication networks—and spectacular auroral lights in the night skies.

The giant blast from the sun was observed through telescopes yesterday morning. More powerful than a billion hydrogen bombs, it is sending a super-heated ball of electrified gas (known as a coronal mass ejection, or CME) straight towards us. The fireball that signalled the event was estimated to be 30 times wider than Earth.

Forecasters at the NOAA Space Environment Center in Boulder, Colorado, expect the fast moving blast from the sun to reach the Earth's magnetic field on Wednesday at about midday, producing predominately a severe G-4 geomagnetic storm with possible periods of extreme G-5 storming. NOAA ranks the severity of such storms on a scale of one to five, which means that this particular solar flare could produce the most severe form of electromagnetic storm on Earth.

When the effects of the flare hit the Earth resulting geomagnetic storms could cause planet-wide communication blackouts and power failures, solar astronomers warn. Other effects may include bright auroras visible across much of Europe and North America and worryingly high levels of radiation.

The geomagnetic storm is expected to last for about 24 hours. Other than the consequences of failures of technology, there is no physical danger to people on the ground.

"This is the real thing," said John Kohl, a solar astrophysicist at the Harvard-Smithsonian Center for Astrophysics (CfA), Cambridge, Massachusetts. "The eruption was positioned perfectly. It's headed straight for us like a freight train, so a major geomagnetic storm is bound to happen when it reaches us," he said in a statement released by CfA.

"This is the strongest flare we've seen in the past 30 years," added Leon Golub, CfA astrophysicist and author of Nearest Star: The Surprising Science of Our Sun.

"It's one of the biggest solar flares ever observed," agreed Robert Walsh, from the Centre for Astrophysics at the University of Central Lancashire, England.

Radio Interference

Two previous fireballs, which left the sun last week, have already caused widespread radio interference. But "last week's CME hit the Earth with only a glancing blow," said Kohl. This latest "eruption was pointed directly at us, and is expected to have major effects."

Astronauts on the International Space Station have been told by NASA to shelter from radiation unleashed by the storm in a specially built Russian module. Airline passengers flying at high altitudes face radiation levels equivalent to a medical chest X-ray.

There are also concerns airline navigational systems may be affected. Other possible impacts of this extreme space weather include disrupted satellite TV reception and huge current surges along power lines. In 1989, a less intense solar flare caused major power cuts in Canada.

The storm may also impede U.S. fire services as they fight to contain raging wildfires in California. Many microwave communication antennas on the ground have been damaged and scientists have told emergency personnel to be prepared for satellite communication interference.

"The most beautiful side effect is increased auroral activity, which people should see at much lower latitudes than normal," Walsh said.

The aurora borealis, or northern lights, could extend as far south as Illinois in the U.S., and London in Europe.

Magnetic Field

Walsh says the solar storm's impact will depend largely on how its magnetic field reacts with that of the Earth.

"If the magnetic fields are oppositely directed they can interact violently and that's when the real fun starts," he said. "We won't know until it actually hits. There's nothing we can do to stop the sun doing this."

Solar flares emanate from darker regions on the sun's surface known as sunspots. These contain intense concentrations of magnetic fields which can become so stressed and tangled they eventually explode, sending up to a billion tons of plasma into space. The region that produced yesterday's flare was 13 times larger than Earth.

NOAA forecasters said the probability of another major flare occurring is high, and additional geomagnetic and radiation storms are likely.

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