Introduction of sunspots
dark spots on the Sun's surface
The ancient Chinese
record observations of sunspots in 165
European actronomers
thoughts about sunspots
didn't believe spots were actually on the sun
reason for this thoughts
belief that the "heavenly"bodies were perfect
opinion about sunspots
The shadow hypotheis-something like shadows of planets crossing the Sun's face
Galileo's finding
the shape of sunspots weren't circular
the shape of sunspots changed
opinion of sunspots
因为seeming to change shape and no predicting changes所以觉得是a feature of the Sun and maybe cloud in the atmosphere
Other hypotheses
the spots were mountains and holes
Heinrich Schwabe's claim
study procedure
look for evidence for 17 years and keep track of and map the sunspots
finding
no planets
sunspots的消长是regular的，并且10y为一个cycle
breakthrough
Wolf
study procedure
keep track of sunspots for 40y
go through old records from various observatories and put together a history of sunspot综合之前100年的
finding
ensure the existence of a patter, a repeating cycle
different from H S
pattern is 11y rather than 10y
It is the same amount of year as the fluctuation of geomagnetic
Scientists in the later 19s
doing studies of possible relationship between the sun and the earth
the sunspots are magnetic field
magnetic fields reduce the pressure exerted on the gases ->make the spots cooler than the rest of the sun's surface->cooler,so darker
