Today's solar lesson

I just subscribed to NASA's weekly podcasts, and learned that:

• sunspots were first seen by Chinese astronomers around 28 BC,


• this year marks a solar minimum (which happens every 11 years) meaning no sunspots for most of the year.

In Year 12 I did a physics experiment involving working out the speed of the sun's rotation, which relies entirely on sunspot measurements. It was really cool to actually draw several pictures of the sunspots (projected onto paper via binoculars) then, through careful measurements (and way more equations than I really needed to use) coming up with an answer very close to the value calculated by real scientists. Would have been a huge anti-climax trying it this year!