Key Ideas

Think about the following questions as you watch the video

1. 01:20 Why is Pluto no longer considered a planet?
2. 12:18 What are some of the benefits of plate tectonic activity?
3. 13:16 Why has our knowledge of planets and solar systems changed in the last 20 years?
4. 02:08 What does it mean to say that the Sun is a second generation star?
5. 04:41 What were some of the materials orbiting the Sun after it formed, and why did the dust begin to stick together (that is, accrete)?
6. 05:57 How long did our Solar System take to get to the form it has today
7. 07:10 What happened to the heavier metals when the planet formed?
8. 07:27 What happened to the gases that rose up from beneath the Earth’s crust and were released in volcanic eruptions?
9. 08:29 The conditions of the Hadean eon were awful, but they did help make the Earth more chemically complex. How?
10. 09:30 When and why did the oceans form?
11. 09:50 Why is the Earth compared to an egg when the discussion of plate tectonics begins in this video?