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Following is a comparison of the growth of cycle 25 versus cycle 24, using the 13-month sunspot averages, beginning with the months of the respective minimums. Numbers in brackets for cycle 25 indicate the minimum possible value for that month, assuming there are no more sunspots between now (Jan 3, 2024) and six months after the end of the ...
One historical long-term correlation between solar activity and climate change is the 1645–1715 Maunder minimum, a period of little or no sunspot activity which partially overlapped the "Little Ice Age" during which cold weather prevailed in Europe. The Little Ice Age encompassed roughly the 16th to the 19th centuries.
Individual sunspots or groups of sunspots may last anywhere from a few days to a few months, but eventually decay. Sunspots expand and contract as they move across the surface of the Sun, with diameters ranging from 16 km (10 mi) [3] to 160,000 km (100,000 mi). [4] Larger sunspots can be visible from Earth without the aid of a telescope. [5]
Many solar phenomena change periodically over an average interval of about 11 years. This solar cycle affects solar irradiation and influences space weather, terrestrial weather , and climate . The solar cycle also modulates the flux of short-wavelength solar radiation, from ultraviolet to X-ray and influences the frequency of solar flares ...
Solar cycle 23 lasted 11.6 years, beginning in May 1996 and ending in January 2008. The maximum smoothed sunspot number (monthly number of sunspots averaged over a twelve-month period) observed during the solar cycle was 120.8 (March 2000), and the minimum was 1.7. [29] A total of 805 days had no sunspots during this cycle. [30] [31] [32]
His statement was confirmed by other specialists in the field. "This is the quietest sun we've seen in almost a century," agreed sunspot expert David Hathaway of the National Space Science and Technology Center NASA/Marshall Space Flight Center. [6] However, the activity is still at a higher level than at a grand solar minimum.
The Solar Cycle 25 Prediction Panel predicted in December 2019 [11] that solar cycle 25 will be similar to solar cycle 24, with the preceding solar cycle minimum in April 2020 (± 6 months), and the number of sunspots reaching a (smoothed) maximum of 115 in July 2025 (± 8 months).
An active region containing a single sunspot or group of sunspots all having the same magnetic polarity. An opposite polarity counterpart is still present, but is weak or not concentrated enough to form sunspots. β: An active region with at least two sunspots or sunspot groups that have opposite magnetic polarity.