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.

My guest today is Dr. Ella Holme, a postdoc at Yale University. Dr. Holme talks about her research on the mineral olivine as a potential antidote for climate change. Olivine can remove carbon dioxide from air and water, and further research into this mineral can help counteract increasing CO2 emissions. We also talk about how olivine is like the Hulk, and how Dr. Holme's path into geology started from childhood fears of tsunamis, climate change, and... werewolves.

Dr. Holme's Twitter: @BandedEllaFrmtn

The Earth of 4.5 billion years ago was perhaps the most alien version of our world, thanks to a collision with a rogue planet. Days and nights were six times shorter, the newborn Moon was as close as a weather satellite, and everything was covered with a sea of magma. Today, we learn how the Moon transformed from a giant Eye of Sauron into our pale nighttime companion.

Extra credit: Squeeze a stress ball, eat only one color of candy, and try to solve this week's hidden word puzzle.

How is new crust made, and why isn't the Earth constantly expanding like a party balloon? To answer these questions, we'll track the life, death, and rebirth of Earth's surface. Stops along the way include the Mid-Atlantic Ridge, a prize-fight between tectonic plates beneath New Zealand, and a stop for dessert on the Italian island of Vulcano.

Extra credit: Experiment with your carpets at home, pushing them together and testing which one sinks beneath the other.

How did the Man in the Moon form? What does the Moon's Far Side look like?

Today, we'll learn about the most visible remnant of the ancient world- the pattern of dark lunar rocks that stares down on us each night. On the way, we'll hitch a ride with a flying fax machine, play a game with crystals in magma, and learn why bananas are slightly radioactive (and why that doesn't really matter).

Extra Credit: Try to send me a fax, or just eat a banana.