Solar cycle 25
Solar cycle 25 is the upcoming and 25th solar cycle since 1755, when extensive recording of solar sunspot activity began. It is expected to begin in late 2019 and continue through 2030. The first Cycle 25 sunspot may have appeared in early April 2018 or even December 2016.
The sun is showing signs of a reverse magnetic polarity sunspot appearing and beginning this solar cycle. It is typical during the end of one cycle and the beginning of the next for there to be a transitional period where sunspots of both polarities exist during the solar minimum. The polarward reversed polarity sunspots suggest that a transition to cycle 25 is indeed in process.
Speculation about the cycle's start date exists. However, authoritative organizations such as the International Solar Energy Society (ISES) and NOAA's Space Weather Prediction Center (SWPC) have not issued or endorsed a scientific forecast for the cycle (as is typical at this stage).
There is also speculation and disagreement as to the expected strength of cycle 25. There is large agreement that it will be weaker than average although disagreement remains on its intensity relative to cycle 24.
- Kane, R.P. (2002). "Some Implications Using the Group Sunspot Number Reconstruction". Solar Physics 205(2), 383-401.
- "The Sun: Did You Say the Sun Has Spots?". Space Today Online. Retrieved 12 August 2010.
- Odenwald, Sten (2016-09-02). "Waiting For The Next Sunspot Cycle: 2019-2030". The Huffington Post. Retrieved 2017-11-22.
- McIntosh, Scott W.; Wang, Xin; Leamon, Robert J.; Davey, Alisdair R.; Howe, Rachel (2014-08-08). "Deciphering Solar Magnetic Activity: On the relationship between the sunspot cycle and the evolution of small magnetic features". The Astrophysical Journal. 792 (1). arXiv:1403.3071. Bibcode:2014ApJ...792...12M. doi:10.1088/0004-637X/792/1/12. Retrieved 2017-11-22.
- "Cycle 25 observations in SDO HMI imagery". Retrieved 2018-05-04.
- Hugh Hudson (10 April 2018). "A Sunspot from Cycle 25 for sure". RHESSI project. Retrieved 2018-11-22.
- Phillips, Tony (November 20, 2018). "A Sunspot from the Next Solar Cycle". SpaceWeather.com. Retrieved 2018-12-13.
- "Coronal hole faces Earth". SpaceWeatherLive.com. Retrieved 2018-04-24.
- "Forecast for Solar Cycle 25". Watts Up With That. Retrieved 16 April 2018.
- Bhowmik, Prantika; D. Nandy (2018). "Prediction of the strength and timing of sunspot cycle 25 reveal decadal-scale space environmental conditions". Nat. Commun. 9 (5209). doi:10.1038/s41467-018-07690-0.