5: Building the Underworld

How did Earth grow from ant-size to, well… Earth-size? What perils did it face along the way? And how is the Earth's interior like a fine vinaigrette? Find out as we move forward in time from 4.6 to 4.5 billion years ago.

Extra credit: try to freeze a mixture of oil and vinegar before they separate, find an iron meteorite at your local museum, or look for Ceres with a pair of binoculars.