11. Solar cycle # 8 ended in 1843, the year that Heinrich Schwabe discovered the sunspot cycle . 12. The journal based its prediction on sunspot cycles . 13. Satellite measurements show some small variations, less than 0.1 percent, in concert with the 11-year sunspot cycle . 14. Solar flares come in 11-year sunspot cycles , and we are approaching a maximum period in the year 2000. 15. The activity of the Sun is associated with the sunspot cycle , with more radiation occurring with more sunspots. 16. Changing radio propagation for long-distance communications due to the 11-year sunspot cycle is a factor at these frequencies. 17. It's a natural part of the sunspot cycle , discovered by German astronomer Heinrich Schwabe in the mid-19th century. 18. Satellite measurements show some small variations, less than 0 . 1 percent, in concert with the 11-year sunspot cycle . 19. "Research work regarding the role of meridional flows in the Sun's interior in setting the period of the sunspot cycle . 20. In these studies he showed that a dominant component was a cosine term of period equal to four sunspot cycles .
