Solar cycle 25 is the upcoming and 25th solar cycle since 1755, when extensive recording of solar sunspot activity began.[1][2] Consensus has not formed over the cycle's start date[3] and expected strength. According to some scientists, it is expected to begin in late 2019 and continue through 2030.[4][5] General agreement holds that it will be weaker than average (i.e. weaker than during Modern Maximum).[6] Organizations such as the International Solar Energy Society (ISES) and NOAA's Space Weather Prediction Center (SWPC) have not issued or endorsed a forecast for the cycle until as late as 2019.
As of April 2018, the sun showed signs of a reverse magnetic polarity sunspot appearing and beginning this solar cycle.[7] It is typical during the transition from one cycle to the next to experience a period where sunspots of both polarities exist (during the solar minimum). The polarward reversed polarity sunspots suggest that a transition to cycle 25 is in process.[8] The first Cycle 25 sunspot may have appeared in early April 2018[9][10] or even December 2016.[8]
Predictions
Consensus has not formed over the cycle's start date[3] and expected strength. Organizations such as the International Solar Energy Society (ISES) and NOAA's Space Weather Prediction Center (SWPC) have not issued or endorsed a forecast for the cycle until as late as 2019. General agreement holds that it will be weaker than average (i.e. weaker than during Modern Maximum).[6]
^ abMcIntosh, Scott W.; Wang, Xin; Leamon, Robert J.; Davey, Alisdair R.; Howe, Rachel; Krista, Larisza D.; Malanushenko, Anna V.; Markel, Robert S.; Cirtain, Jonathan W.; Gurman, Joseph B.; Pesnell, William D.; Thompson, Michael J. (8 August 2014). "Deciphering Solar Magnetic Activity: On the relationship between the sunspot cycle and the evolution of small magnetic features". The Astrophysical Journal. 792 (1): 12. arXiv:1403.3071. Bibcode:2014ApJ...792...12M. doi:10.1088/0004-637X/792/1/12.
^ abcBhowmik, Prantika; Nandy, Dibyendu (6 December 2018). "Prediction of the strength and timing of sunspot cycle 25 reveal decadal-scale space environmental conditions". Nature Communications. 9 (1): 5209. Bibcode:2018NatCo...9.5209B. doi:10.1038/s41467-018-07690-0. PMID30523260.
^Shepherd, Simon J.; Zharkov, Sergei I.; Zharkova, Valentina V. (13 October 2014). "Prediction of solar activity from solar background magnetic field variations in cycles 21-23". The Astrophysical Journal. 795 (1): 46. Bibcode:2014ApJ...795...46S. doi:10.1088/0004-637X/795/1/46.
^Li, F.Y.; Kong, D.F.; Xie, J.L.; Xiang, N.B.; Xu, J.C. (December 2018). "Solar cycle characteristics and their application in the prediction of cycle 25". Journal of Atmospheric and Solar-Terrestrial Physics. 181: 110–115. Bibcode:2018JASTP.181..110L. doi:10.1016/j.jastp.2018.10.014.
