'Noticed by Galileo in 1610, these on the sun wax & wane in 11-year cycles'
sunspots
10-12 YEARS: Noticed by Galileo in 1610, these on the sun wax & wane in 11-year cycles
Noticed by Galileo in 1610, these on the sun wax & wane in 11-year cycles
Noticed by Galileo in 1610, these on the sun wax & wane in 11-year cycles
10-12 YEARS
sunspots
10-12 YEARS