We finally start the tale of Earth’s history from the beginning, in the cold depths of outer space. The Sun is born and the first asteroids assemble. When these asteroids crash into Earth today, they provide time capsules from the beginning of the solar system.

Extra credit: look for the Orion Nebula in the night sky, or go meteorite hunting with a friend.

How did Earth grow from ant-size to, well… Earth-size? What perils did it face along the way? And how was the early Earth like a fine vinaigrette?

Extra credit: try to freeze a mixture of oil and vinegar before they separate.

Today, we'll learn how deep humans have traveled into the planet, and how we know what's even deeper down. We'll meet mineral oozes, coils of liquid iron, and a Danish woman from the 1930s who discovered the center of the Earth.

Extra credit: Make a tin-can telephone, find an inductor in one of your electric appliances, or look for an aurora.

Earth's first oceans were hundreds of times deeper than the Pacific and made of molten rock. Where did they come from, where did they go? What stuff was in them, how do we know? Today, let's dive in and see how these oceans turned into today's mantle.

Extra credit: Drink a glass of ice water, watch The Core (2003), or see if you can find a garnet in your home or a museum.