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The @stro object for the week of 03/06/2000

image of sunspots

image courtesy of SOHO

Sunspots. Sunspots are large, dark, rapidly changing areas on the Sun's surface that can be up to 50,000 miles in diameter. Sunspots usually only last a few days, although they can last as long as weeks or months.

While the nature of how they are developed is still a subject of research they are believed to be caused by areas of high magnetic activity blocking some solar energy from entering these regions. The blocking of this energy results in colder temperatures than the surrounding photosphere and the darker appearance.

Sunspots are often used as a predictor of solar activity. The number of sunspots increases and decreases on a fairly regular schedule. The Sun's cycle is broken up into two phases: the "solar maximum", which is the highest point of solar activity, and the "solar minimum", which is the lowest part of solar activity. The length of the solar cycle averages around 11 years from one solar maximum (or minimum) to the next. Sunspots are at their lowest numbers during solar minimum and at their peak numbers during solar maximum, in direct correlation to this cycle . Currently the Sun is entering a period of maximum activity.

Sunspots can easily be seen with a small telescope or binoculars fitted with proper solar filtering. REMEMBER: NEVER LOOK AT THE SUN DIRECTLY WITHOUT PROPER SOLAR FILTERS IN PLACE. Visit the SOHO site to view images taken in several wavelengths of light.

Current information for the Sun (North America):
Rise: 0628 PST
Set: 1802 PST
Magnitude: -26.8
Constellation: Aquarius

more info from the Exploratorium...

more info on the solar cycle...

more info from APOD

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