Solar cycle 23
Solar cycle 23 | |
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The Sun, with some sunspots visible, during solar cycle 23 (2003).
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Sunspot Data | |
Start date | May 1996 |
End date | January 2008 |
Duration (years) | 11.7 |
Max count | 120.8 |
Max count month | March 2000 |
Min count | 1.7 |
Spotless days | 821 |
Cycle chronology | |
Previous cycle | Solar cycle 22 (1986-1996) |
Next cycle | Solar cycle 24 (2008-) |
Solar cycle 23 was the 23rd solar cycle since 1755, when extensive recording of solar sunspot activity began.[1][2] The solar cycle lasted 12.6 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.[3] A total of 805 days had no sunspots during this cycle.[4][5][6]
Contents
History
One of the first major aurora displays of solar cycle 23 occurred on 6 April 2000, with bright red auroras visible as far south as Florida and South Europe.[7] On 14 July 2000, the Coronal Mass Ejection (CME) hurled by a X5.7 solar flare provoked an extreme (G5 level) geomagnetic storm the next day. Known as the Bastille day event, this storm caused damage to GPS systems and some power companies.[citation needed] Auroras were visible as far south as Texas.[8] Another major aurora display was observed on 1 April 2001, due to a coronal mass ejection hitting the Earth's magnetosphere. Auroras were observed as far south as Mexico and South Europe. A large solar flare (the second-most powerful ever recorded) occurred on 2 April 2001, an X20-class, but the blast was directed away from Earth.
In late October 2003, a series of large solar flares occurred. A X17.2-class flare ejected on 28 October 2003 produced auroras visible as far south as Florida and Texas. A G5 level geomagnetic storm blasted the Earth's magnetosphere the next two days.[9] A few days later, the largest solar flare ever measured with instruments occurred on 4 November; initially measured at X28, it was later upgraded to an X45-class.[10][11] This flare was not Earth-oriented and thus only resulted in high-latitude auroras. The whole sequence of events occurred from 28 October to 4 November is known as the Halloween Solar Storm. Other large solar flares occurred on 7 September 2005 (X17), 15 April 2001 (X14.4) and 29 October 2003 (X10), with auroras visible in mid-latitudes.
See also
References
- ↑ Kane, R.P. (2002). "Some Implications Using the Group Sunspot Number Reconstruction". Solar Physics 205(2), 383-401.
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External links
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