houghtonlib:Galileo didn’t know it at the time, but his observations of sunspot activity in
houghtonlib: Galileo didn’t know it at the time, but his observations of sunspot activity in 1612 were tailor-made for the animated GIF! He demonstrated that sunspots can be tracked across the disk of the sun as it rotates–look for the cluster labeled R moving from top left to lower right. Galilei, Galileo, 1564-1642. Istoria e dimostrazioni intorno alle macchie solari e loro accidenti, 1613. *IC6.G1333.613ia Houghton Library, Harvard University -- source link
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