Solar cycle 9

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Solar cycle 9
Sunspot Data
Start date July 1843
End date December 1855
Duration (years) 12.4
Max count 131.9
Max count month February 1848
Min count 3.2
Spotless days 654
Cycle chronology
Previous cycle Solar cycle 8 (1833-1843)
Next cycle Solar cycle 10 (1855-1867)

During solar cycle 9, Edward Sabine and other scientists linked solar cycles to geomagnetic cycles.

Solar cycle 9 was the ninth solar cycle since 1755, when extensive recording of solar sunspot activity began.[1][2] The solar cycle lasted 12.4 years, beginning in July 1843 and ending in December 1855. The maximum smoothed sunspot number (monthly number of sunspots averaged over a twelve-month period) observed during the solar cycle was 131.9 (February 1848), and the minimum was 3.2.[3] There were a total of approximately 654 days with no sunspots during this cycle.[4][5][6]

Solar cycle 9 began in 1843, the year that Heinrich Schwabe discovered the sunspot cycle.[7] During this cycle, Edward Sabine, Rudolf Wolf, and other scientists recognized that solar disturbances affected the Earth's magnetic environment, so that solar cycles are identical to the Earth's geomagnetic cycles. Wolf also introduced the Wolf number during this period.

Geomagnetic activity during solar cycle 9 followed a double-peaked distribution, with more magnetic storms during the rising (1847–48) and falling (1851–54) parts of the cycle.[8]

See also[edit]


  1. ^ Kane, R.P. (2002). "Some Implications Using the Group Sunspot Number Reconstruction". Solar Physics 205(2), 383-401.
  2. ^ "The Sun: Did You Say the Sun Has Spots?". Space Today Online. Retrieved 12 August 2010. 
  3. ^ SIDC Monthly Smoothed Sunspot Number. "[1]"
  4. ^ Spotless Days. "[2]"
  5. ^ What's Wrong with the Sun? (Nothing) more information: Spotless Days. "[3]"
  6. ^ Solaemon's Spotless Days Page. "[4]"
  7. ^ Claudio Vita-Finzi. Solar History: An Introduction, p. 4, Springer, 2012 ISBN 9400742959.
  8. ^ Nevanlinna, H.; Ketola, A.; Häkkinen, L.; Viljanen, A.; Ivory, K. (23 April 1993). "Geomagnetic activity during solar cycle 9 (1844–1856)". Geophysical Research Letters 20 (8): 743–746. doi:10.1029/93GL00836.