[PHOTO: Sunspot unleashes charged particles; level of disruption is in line with forecasts. An ultraviolet view of the sun, captured by the Solar and Heliospheric Observatory on Friday, shows eruptions from two major sunspots facing Earth]

A strong dose of space weather hit Earth on Friday — but the initial storm of charged particles from the sun wasn’t enough to endanger power grids, as feared. The event is presenting a nice opportunity to view sunspots, though safe viewing techniques must be employed to prevent eye damage. Check for updates as the day goes on at

THE STORM of charged particles was unleashed by a dark region on the solar surface called Sunspot 484. The huge spot, about the size of Jupiter’s surface, has been growing for several days and rotating into a position that now points squarely at Earth.


Another giant sunspot could generate additional storms. Sunspots are cooler regions of the sun where magnetic energy wells up, often prior to eruptions.

The sunspot let loose a storm of energetic particles, known as a coronal mass ejection, at 3 a.m. ET Wednesday, according to forecasters at the National Oceanic and Atmospheric Administration. The expanding cloud arrived at 11:30 a.m. ET Friday, producing a geomagnetic storm rated G3 on a scale that goes up to G5.

Space storms occur when the sun throws off an outburst of radiation and energetic particles that can interact with Earth's magnetic field. Such storms can disrupt communications, damage satellites and even pose health risks. The National Oceanic and Atmospheric Administration has set up three scales to measure the severity of "space weather." Click on a category above to see what effects each level of space storm can create:

G5: Extreme. Collapse of power grid systems, damage to transformers, satellite link problems, radio disruption.

G4: Severe. Potential problems with stability of power grids, satellite corrections needed, radio communications affected.

G3: Strong. Voltage corrections required, false alarms triggered on protection devices, satellite problems, intermittent radio problems.

G2: Moderate. High-latitude power systems affected, possible effect on satellite orbits, fading in high-frequency radio signals at high latitudes.

G1: Minor. Weak power grid fluctuations, minor impact on satellite operations, migratory animals begin to be affected.

S5: Extreme. High radiation hazard for spacewalkers. Passengers in high-flying aircraft at high latitudes may receive radiation dose equivalent to chest X-ray. Some satellites lost. No high-frequency communications possible in polar regions.

S4: Severe. Radiation hazard for spacewalkers. Satellites encounter problems. Some blackouts in high-frequency communications in polar regions.

S3: Strong. Spacewalkers should take measures to avoid radiation hazard. Single-event satellite upsets. Degraded high-frequency communications in polar regions.

S2: Moderate. No biological impact. Infrequent single-event satellite upsets. Small effects on high-frequency communications.

S1: Minor. No biological impact. No impact on satellite operations. Minor impact on high-frequency radio in polar regions.

R5: Extreme. Complete high-frequency radio blackout on Earth’s sunlit side for several hours. Low-frequency outages. Increased navigation errors.

R4: Severe. High-frequency radio blackout for one or two hours, affecting most of Earth’s sunlit side. Low-frequency outages. Minor disruptions in satellite navigation systems.

R3: Strong. Wide-area blackout of high-frequency radio on sunlit side. Low-frequency signals degraded for about an hour, affecting navigation systems.

R2: Moderate. Limited blackouts of high-frequency radio on sunlit side. Low-frequency navigation signals degraded for tens of minutes.

R1: Minor. Minor degradation of high-frequency radio on sunlit side. Low-frequency navigation signals degraded for brief intervals.

The activity is expected to generate a colorful aurora, or Northern Lights, down to the northern United States and much of northern Europe. Meanwhile, a continuing “coronal hole” is already providing aurorae farther north, in places like Alaska and northern Canada.

The storm comes as the sun is actually in a declining mode of activity. An 11-year solar cycle peaked during 2001 and 2002. Sunspots are fewer now, and activity will ramp down during the next three to four years. But, scientists say, isolated severe space weather can occur at any time.

“It’s somewhat unusual to have this much activity when we’re approximately three and a half years past solar maximum,” said Larry Combs, a forecaster with the NOAA Space Environment Center’s Space Weather Operations. “In fact, just last week, solar activity was very low with an almost spotless sun.”

Space weather has hampered satellite communications before.

In 1997, an AT&T Telstar 401 satellite used to broadcast television shows from networks to local affiliates was knocked out during a solar storm. In May 1998 a space storm disabled PanAmSat’s Galaxy 4, used for automated teller machines and airline tracking services, among other things. Another storm in July 2000 put several satellites temporarily out of contact and caused navigation problems in others.

• Cell Phone Drops Calls? Blame the Sun

Warning of impending storms allows satellite operators to reduce the risk of damage to some satellites by shutting down electronics.

Even cell phones can act up during solar storms, causing dropped calls.

In 1989, a solar storm tripped protective switches in Canadian Hydro-Québec power company. All of Québec lost power for nine hours. The problem nearly spread to the United States through an interconnected grid. Power companies have since developed programs to safeguard their systems, but experts say they remain at risk.

Forecasters said a second sunspot, developing and about to rotate into an effective position on the sun’s surface, could produce additional stormy weather over the next couple of weeks. In fact, early Thursday it unleashed a major flare of its own, one that could generate some space weather near Earth even though it wasn’t pointed directly at us. That glancing blow would arrive late Friday or, more likely, Saturday.

Sunspots can be seen from home with proper, safe viewing techniques. Astronomers suggest projecting the sun’s image through binoculars onto a white surface. Never look directly at the sun, however, either with the naked eye or through binoculars or telescopes.

MSNBC’s Alan Boyle updated this report. © 2003 All rights reserved.

Reported by: Sol Jose Vanzi

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