The lecture video is embedded below but also available here in MP4 format. Additionally, slides used in the lecture are embedded below but also are available here in Powerpoint format. Questions after the lecture? Please ask them in here.
You talked a moment about an astronaut seeing an earth eclipse while on the moon. I think someone would have to spend two weeks on the moon for that to happen. I don't know so I'm writing you to see if you think this is true. The rocket energy to reach the moon is least when the moon is leading or trailing the earth in our orbit about the sun at first or third quarter. At these lunar phases we don't have to fight the sun's gravitational pull. Make sense?