Saturday, July 12, 2008

Nothing unusual with the sun - says the man who said the sun is behaving unusually

Davd Hathaway, NASA scientist, seeks to calm fears that the sun's low level of activity is unusual.

Nothing is out of whack with the sun, a NASA researcher said this week, despite some scientists' suggestions that a lull in the weather there lately is unusually long, a phenomenon linked to at least one small ice age.

"There have been some reports lately that solar minimum is lasting longer than it should. That's not true," said NASA solar physicist David Hathaway.

Hathaway has studied sunspot data going back to 1749. While the cycle is commonly said to last 11 years, in fact its length can vary by more than a year.

"We have already observed a few sunspots from the next solar cycle," he said. "This suggests the solar cycle is progressing normally."

OK. Although Hathaway fails to point out that the "few sunspots" were very few, very tiny and the sort of thing that probably would not have been picked up during the latter part of the 17th century. I'm not sure they'd even have been picked up during much of the 20th century.

The first Solar Cycle 24 sunspot appeared on January 4th 2008 - a tiny little speck of a sunspot that disappeared almost as soon as it arrived. Since then Solar Cycle 23 sunspots have been detected - still - but no more from 24. As I write this there have been 18 continuous days with no visible sunspots.

Still nothing unusual about that - but this is unusual.

May 10, 2006: The Sun's Great Conveyor Belt has slowed to a record-low crawl. "It's off the bottom of the charts. This has important repercussions for future solar activity."

The Great Conveyor Belt is a massive circulating current of fire (hot plasma) within the Sun. It has two branches, north and south, each taking about 40 years to perform one complete circuit. Researchers believe the turning of the belt controls the sunspot cycle, and that's why the slowdown is important.

"Normally, the conveyor belt moves about 1 meter per second—walking pace - that's how it has been since the late 19th century."

In recent years, however, the belt has decelerated to 0.75 m/s in the north and 0.35 m/s in the south. "We've never seen speeds so low."

According to theory and observation, the speed of the belt foretells the intensity of sunspot activity ~20 years in the future. A slow belt means lower solar activity; a fast belt means stronger activity.

So that would be "unusual" then? And who was it saying all this?

NASA solar physicist David Hathaway.

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