Web Seminar make-up activity

I thought that this web seminar was very interesting. I have always been fascinated with astronomy, so it was wonderful having the opportunity to learn a little more about the subject! One thing that I learned from this seminar is that approximately 13.5 billion years ago the milky way galaxy was actually a nebula! I also learned about how stars are classified by using a spectra, which provides information on temperature, composition, brightness, and in some cases, distance. Another thing that I found interesting was the differences between hot and cool stars. An O star is considered to be a very hot star at 20 degrees K. An M star is considered a cool star, coming in at around 3000 degrees K. Our sun is a G5 star, which is close to 6000 degrees K. I also found it interesting that cool stars actually have molecules surrounding their atmosphere; while hot stars only have elements.