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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 ...
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]
Solar maximum is the regular period of greatest solar activity during the Sun's 11-year solar cycle. During solar maximum, large numbers of sunspots appear, and the solar irradiance output grows by about 0.07%. [2] On average, the solar cycle takes about 11 years to go from one solar maximum to the next, with duration observed varying from 9 to ...
The sun emits the largest solar flare of this 11-year cycle, as imaged by NASA's Solar Dynamics Observatory on October 3. NASA/SDO NASA says the sun is in the highly active "maximum phase" of its ...
In 2002, Lean et al. [41] stated that while "There is ... growing empirical evidence for the Sun's role in climate change on multiple time scales including the 11-year cycle", "changes in terrestrial proxies of solar activity (such as the 14C and 10Be cosmogenic isotopes and the aa geomagnetic index) can occur in the absence of long-term (i.e ...
This index (also known as the Zürich number) uses both the number of sunspots and the number of sunspot groups to compensate for measurement variations. A 2003 study found that sunspots had been more frequent since the 1940s than in the previous 1150 years. [30] Sunspots usually appear as pairs with opposite magnetic polarity. [31]
Solar minimum is the regular period of least solar activity in the Sun's 11-year solar cycle. During solar minimum, sunspot and solar flare activity diminishes, and often does not occur for days at a time. On average, the solar cycle takes about 11 years to go from one solar minimum to the next, with duration observed varying from 9 to 14 years.
In 2006, NASA predicted that the next sunspot maximum would reach between 150 and 200 around the year 2011 (30–50% stronger than cycle 23), followed by a weak maximum at around 2022. [50] [51] Instead, the sunspot cycle in 2010 was still at its minimum, when it should have been near its maximum, demonstrating its unusual weakness. [52]