Page

Volume 4, Issue 1

With the appearance of Sunspot 981 -- a high-latitude, reversed polarity sunspot -- on Friday, January 4, experts at NASA and the National Oceanic and Atmospheric Administration (NOAA) said that Cycle 24 is now here. "This sunspot is like the first robin of spring," said solar physicist Douglas Biesecker of the Space Weather Prediction Center (SWPC), part of NOAA. "In this case, it's an early omen of solar storms that will gradually increase over the next few years."

Solar physicist David Hathaway of NASA's Marshall Space Flight Center in Huntsville, Alabama concurred, saying that new solar cycles begin with a "modest knot" of magnetism, like the one that appeared on December 11 on the east limb of the Sun: "That patch of magnetism could be a sign of the next solar cycle. New solar cycles always begin with a high-
Text Box: latitude, reversed polarity sunspot." The region of magnetism that appeared back in December achieved high latitude (24 degrees North) and was magnetically reversed, but no supporting sunspot appeared until 25 days later. Reversed polarity means a sunspot with opposite magnetic polarity compared to sunspots from the previous solar cycle. High-latitude refers to the Sun's grid of latitude and longitude. Old-cycle spots congregate near the Sun's equator; new-cycle spots appear higher, around 25 or 30 degrees latitude. Sunspot 981's high-latitude location at 27 degrees North and its negative polarity leading to the right in the Northern Hemisphere are clear-cut signs of a new solar cycle, according to NOAA experts. The first active regions and sunspots of a new solar cycle can emerge at high latitudes while those Text Box: from the previous cycle continue to form closer to the equator. Solar Cycle 24 Predictions While experts vary in their predictions on when the solar cycle will peak and how strong it will be, NOAA, in April 2007, in coordination with an international panel of solar experts, predicted that the next 11-year cycle of solar storms "would start in March 2008, plus or minus six months, and peak in late 2011 or mid-2012." In the cycle forecast issued in April 2007, half of the panel predicted a "moderately strong cycle of 140 sunspots, plus or minus 20, expected to peak in October 2011. The other half predicted a moderately weak cycle of 90 sunspots, plus or minus 10, peaking in August 2012. An average solar cycle ranges from 75 to 155 sunspots. [Continued on page 3]

Cycle 24 Here, Experts Say

Text Box: This chart shows the progression of Solar Cycle 23. With experts claiming Solar Cycle 24 is now here, they expect a strong and vibrant solar cycle peaking somewhere around 2011-2012. [Photo courtesy NOAA/Space Weather Prediction Center]