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Rare Sunspot Absences Reported

Posted on: Tuesday, 19 October 2004, 12:00 CDT

For the first time in almost 10 months, no sunspots were visible on the sun recently, U.S. scientists reported, which suggests the solar maximum is imminent.

Sunspots are planet-sized islands on the sun's surface of the sun that are dark, cool and powerfully magnetized. They also are fleeting, lasting only a few days or weeks. As soon as one disappears, another emerges to take its place.

Two solar physicists at NASA's Marshall Spaceflight Center, who have been checking the sun every day since 1998, said the absence of sunspots on Oct. 11 and oct. 12 is a sign that the solar minimum is coming, and it's coming sooner than we expected.

Solar minimum and maximum are two extremes of the sun's 11-year activity cycle. At solar maximum, the sun is peppered with spots, solar flares erupt, and the sun hurls billion-ton clouds of electrified gas toward Earth, where they can threaten astronauts in orbit, disable satellites, and even knock out electric power grids on the surface.

At solar minimum, sunspots sometimes disappear for days or weeks, solar flares subside, and it becomes safer to travel through space.

Based on their calculations, the scientists said the solar minimum should arrive in late 2006, about a year earlier than previously thought.

Source: United Press International

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