Key Ideas

Think about the following questions as you watch the video

1. 00:39 What are two different reasons that stars appear to differ in brightness?
2. 01:12 What is a spectrum?
3. 01:32 What does it mean that a star gives off a continuous spectrum?
4. 01:50 What does a star’s atmosphere do to its continuous wavelength?
5. 02:25 What did Max Planck determine about bluer versus redder stars?
6. 03:12 How does today’s star classification system arrange stars?
7. 03:44 What letter classification is our Sun?
8. 04:33 Why are there no green stars?
9. 05:37 What is luminosity?
10. 05:57 What two things does a star’s luminosity depend upon?
11. 07:10 Describe the three groups of stars Hertzsprung and Russell saw when they plotted a chart of stars’ luminosity versus its temperature.