Solar minimum
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Solar minimum is the period of least solar activity in the solar cycle of the sun. During this time sunspot and solar flare activity diminishes, and often does not occur for days at a time. The date of the minimum is described by a smoothed average over 12 months of sunspot activity, so identifying the date of the solar minimum usually can only happen 6 months after the minimum takes place.
Solar minimum is contrasted with the solar maximum, where there may be hundreds of sunspots.
Solar minimum and solar maximum--"Solar Min" and "Solar Max" for short--are two extremes of the sun's 11-year activity cycle. At maximum, the sun is peppered with spots, solar flares erupt, and the sun hurls billion-ton clouds of electrified gas toward Earth. It's a good time for sky watchers who enjoy auroras, but not so good for astronauts who have to be wary of radiation storms. Power outages, disrupted satellite functions and communications, malfunctioning GPS receivers--these are just a few of the things that can happen during Solar Max.
Solar minimum is different. Sunspots are fewer--sometimes days or weeks go by without a spot. Solar flares subside. It's a safer time to travel through space, and a less interesting time to watch polar skies.
As of this writing, in April 2006, the sun is ending a solar minimum period.[1]
[edit] Effects of solar minimum
Solar minimum is characterized by a period of minimum solar activity with little, if any, sunspots. Generally, this is the safest time for astronauts to do their missions due to an associated decrease in solar radiation. During solar minimum scientists can predict the next two solar cycles using the solar "conveyer belt". If the conveyer belt is moving rapidly it will sweep up lots of old magnetic fields on the sun's surface to the sun's center, eventually returning to the surface as lots of new sunspots. The opposite is true when the conveyer belt is moving slowly since fewer old magnetic fields are being swept down. Using this method of forecasting Solar Cycle 25 will be a very mild cycle with few sunspots even during solar maximum.
[edit] References
http://science.nasa.gov/headlines/y2006/10may_longrange.htm Solar Cycle 25 peaking around 2022 could be one of the weakest in centuries.
[edit] See also
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| Structure: Solar Core - Radiation Zone - Convection Zone |
| Atmosphere - Photosphere - Chromosphere - Transition region - Corona |
| Extended Structure: Termination Shock - Heliosphere - Heliopause - Heliosheath - Bow Shock |
| Solar Phenomena: Sunspots - Faculae - Granules - Supergranulation - Solar Wind - Spicules |
| Coronal loops - Solar Flares - Solar Prominences - Coronal Mass Ejections |
| Moreton Waves - Coronal Holes |
| Other: Solar System - Solar Variation - Solar Dynamo - Heliospheric Current Sheet - Solar Radiation - Solar Eclipse |
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