Learn what's at the center of Earth and how our planet is still being formed today. See evidence that Earth has been touched by asteroids from outer space.

What does Earth look like from space? -- Why does Earth have seasons? -- Why can we breathe on Earth? -- How high is the sky? -- What is Earth's surface like? -- What is the Earth made of? -- How was Earth made? -- When did life begin on earth? -- Fact file -- Glossary.