Solar cycle 24

Solar Cycle 24 is the 24th solar cycle since 1755, when extensive recording of solar sunspot activity began. It is the current solar cycle, and began in December 2008 with a smoothed minimum of 2.2 (SIDC formula). Activity was minimal until early 2010. It reached its maximum in April 2014 with a 23 months smoothed sunspot number of only 81.8, comparable to those of cycles 12 through 15. Reversed polarity polar active sunspot regions in December 2016, April 2018, November 2018, May 2019, and July 2019 indicate that a transitional phase to solar cycle 25 is in process.Video captured by NASA's Solar Dynamics Observatory of the initial ejection taken August 1, 2010.The coronal mass ejection starts at 2:36 UTC and ends at 3:56 UTC on August 1, 2010 in this animation on STEREO Ahead images.This eruption is directed right at us and is expected to get here early in the day on August 4. It's the first major Earth-directed eruption in quite some time. When such an expulsion reaches Earth, it interacts with the planet's magnetic field and can create a geomagnetic storm. Solar particles stream down the field lines toward Earth's poles. Those particles crash with atoms of nitrogen and oxygen in the atmosphere, which then glow like little neon signs. Sky watchers in the northern U.S. and other countries should look toward the north late Tuesday or early Wednesday for rippling 'curtains' of green and red light.Solar northern hemisphere during the first eruption as seen in extreme ultraviolet by the Solar Dynamics Observatory.SDO multi-wavelength image of the August 1, 2010 event. Solar Cycle 24 is the 24th solar cycle since 1755, when extensive recording of solar sunspot activity began. It is the current solar cycle, and began in December 2008 with a smoothed minimum of 2.2 (SIDC formula). Activity was minimal until early 2010. It reached its maximum in April 2014 with a 23 months smoothed sunspot number of only 81.8, comparable to those of cycles 12 through 15. Reversed polarity polar active sunspot regions in December 2016, April 2018, November 2018, May 2019, and July 2019 indicate that a transitional phase to solar cycle 25 is in process. Prior to the minimum between the end of Solar Cycle 23 and the beginning of Solar Cycle 24, two theories predicted how strong Solar Cycle 24 would be. One camp postulated that the Sun retained a long memory (Solar Cycle 24 would be active) while the other asserted that it had a short memory (quiet). Prior to 2006, the difference was substantial with a minority of researchers predicting 'the smallest solar cycle in 100 years.' Another group of researchers, including one at NASA, predicted that it 'looks like its going to be one of the most intense cycles since record-keeping began almost 400 years ago.' The delayed onset of high latitude spots indicating the start of Solar Cycle 24 led the 'active cycle' researchers to revise their predictions downward and the consensus by 2007 was split 5-4 in favor of a smaller cycle. By 2012, consensus was a small cycle, as solar cycles are much more predictable 3 years after minima. In May 2009 the NOAA Space Weather Prediction Center's Solar Cycle 24 Prediction Panel predicted the cycle to peak at 90 sunspots in May 2013. In May 2012 NASA's expert David Hathaway predicted a peak in Spring of 2013 with about 60 sunspots. NASA funded and used Ken Schatten's physics-based models, which utilized a solar Dynamo model to accurately predict the low. This method used the correlation between solar magnetic field strength at solar minimum to sun spot number at solar maximum to accurately predict the peak solar flux of each of the last three solar cycles. Schatten's predictions become accurate as early as solar minima, 5–6 years before solar max. In early 2013, after several months of calm, it was obvious that the active 2011 was not a prelude to a widely predicted late 2012-early 2013 peak in solar flares, sunspots and other activity. This unexpected stage prompted some scientists to propose a 'double-peaked' solar maximum, which then occurred. The first peak reached 99 in 2011 and the second peak came in early 2014 at 101. According to NASA, the intensity of geomagnetic storms during Solar Cycle 24 may be elevated in some areas where the Earth's magnetic field is weaker than expected. This fact was discovered by the THEMIS spacecraft in 2008. A 20-fold increase in particle counts that penetrate the Earth's magnetic field may be expected. Solar Cycle 24 has been the subject of various hypotheses and commentary pertaining to its potential effects on Earth. While acknowledging that the next solar maximum will not necessarily produce unusual geomagnetic activity, astrophysicist Michio Kaku took advantage of the media focus on the 2012 phenomenon to draw attention to the need to develop strategies for coping with the terrestrial damage that such an event could inflict. He asserted that governments should ensure the integrity of electrical infrastructure, so as to prevent a recurrence of disruption akin to that caused by the solar storm of 1859. The current solar cycle is currently the subject of research, as it is not generating sunspots in the expected manner. Sunspots did not begin to appear immediately after the last minimum (in 2008) and although they started to reappear in late 2009, they were at significantly lower rates than anticipated.