kosmos: Solar cycle 20

Evidence: 100 • authority: 72

Solar cycle 20 was the twentieth solar cycle since 1755, when extensive recording of solar sunspot activity began. The solar cycle lasted 11.4 years, beginning in October 1964 and ending in March 1976. The maximum smoothed sunspot number observed during the solar cycle was 156.6 (November 1968), and the starting minimum was 14.3. During the minimum transit from solar cycle 20 to 21, there were a total of 272 days with no sunspots. Comparison with other cycles shows that geomagnetic activity during the declining phase of cycle 20 (1973–1975) was unusually high. Heavy solar activity was a factor in causing the earlier-than-expected atmospheric reentry of Skylab in 1979. Data from solar cycle…

Evidence: 91 • authority: 72

Solar cycle 19 was the nineteenth solar cycle since 1755, when extensive recording of solar sunspot activity began. The solar cycle lasted 10.5 years, beginning in April 1954 and ending in October 1964. The International Geophysical Year occurred at the peak of this solar cycle. The maximum smoothed sunspot number observed during the solar cycle was 285.0, in March 1958 (the highest on record), and the starting minimum was 5.1. During the minimum transit from solar cycle 19 to 20, there were a total of 227 days with no sunspots. This was the lowest number since 1850.

Evidence: 82 • authority: 72

Solar cycle 24 is the most recently completed solar cycle, the 24th since 1755, when extensive recording of solar sunspot activity began. It began in December 2008 with a minimum smoothed sunspot number of 2.2, and ended in December 2019. Activity was minimal until early 2010. It reached its maximum in April 2014 with a 23 months smoothed sunspot number of 81.8. This maximum value was substantially lower than other recent solar cycles, down to a level which had not been seen since cycles 12 to 15 (1878-1923).

Evidence: 82 • authority: 72

Solar cycle 23 was the 23rd solar cycle since 1755, when extensive recording of solar sunspot activity began. The solar cycle lasted 12.6 years, beginning in August 1996 and ending in December 2008. The maximum smoothed sunspot number observed during the solar cycle was 180.3 (November 2001), and the starting minimum was 11.2. During the minimum transit from solar cycle 23 to 24, there were a total of 817 days with no sunspots. Compared to the last several solar cycles, it was fairly average in terms of activity.

Evidence: 82 • authority: 72

Solar cycle 25 is the current solar cycle, the 25th since 1755, when extensive recording of solar sunspot activity began. It began in December 2019 with a minimum smoothed sunspot number of 1.8. It is expected to continue until about 2030. While it was initially predicted by most scientists that cycle 25 would be relatively weak, solar activity has been much stronger than the predictions.

Evidence: 45 • authority: 88

Sunspot number solar cycle clock based prediction of cycle 26 maximum. The overall level of activity of the solar cycle, as seen in the sunspot number (SSN) record, paces both the amplitude and occurrence rates of extreme space weather events [1] and the state of the ionosphere [2]. Predictions of future solar activity levels can be critical to assess system resilience and for planning. For example, under-prediction of current cycle 25 led to under-estimation of drag in LEO, with significant impact on satellite operations [3,4]. SSN predictions on solar cycle timescales are however challenging as no two past cycles have the same amplitude or duration. One method is that of precursors, that…

Evidence: 36 • authority: 92

A 903-year annual temperature reconstruction for the southeastern tibetan plateau from the tree ring widths of Juniperus saltuaria.. Precisely dated paleoclimatic records are essential for understanding natural and anthropogenic climate influences. Here, an annually resolved absolutely dated Juniperus saltuaria tree ring width chronology from the Haizi mountain, southeastern Tibetan Plateau (TP) was developed. The chronology shows the annual- to decadal-scale paleoclimatic variability of the southeastern TP over the past 903 years (1115-2017 CE). The tree ring widths correlate significantly with mean annual temperature (T mean ). A linear regression model between ring width and T mean , acc…

Evidence: 27 • authority: 80

The solar wind cycle, the sunspot cycle, and the corona

Evidence: 27 • authority: 80

Revised sunspot cycle predicts highly active solar period

Evidence: 27 • authority: 92

Relation of pandemics with solar cycles through ozone, cloud seeds, and vitamin D.. The global records of infectious diseases, including Western and Eastern documents from 1825 to 2020, during which sunspot observations are considered reliable, show that 27 of the 34 pandemic outbreaks were coincident with sunspot number maxima or minima. There is evidence that the intensity of galactic cosmic rays is anti-correlated with solar activity and that cloud seed formation is accelerated by galactic cosmic rays. There are a substantial number of research papers showing the relationship between COVID-19 and vitamin D deficiency. The data analysis of ozone thickness measured based on NASA satellite…