What is the oldest thing on our planet? How old is it, and where was it found?

Today, we tell the story of a worldwide, decades-long hunt for a single grain of sand. We'll journey to underground magma chambers, the sun-baked Australian Outback, and the lair of a giant shrimp.

Extra credit: Let a handful of sand run through your fingers, or go pressure-wash something.

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, with the help of a Canadian geologist, some homemade lava, and a bucket of water.

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

My guest today is Dr. Nadja Drabon, a new professor at Harvard University. Dr. Drabon talks about her new discoveries of zircon crystals from South Africa that are more than 4 billion years old, some of the oldest fragments of Earth. Together, we learn just how much we don't know about Earth's earliest days, and what her discoveries can teach us about our planet's ancient secrets. We also talk about her field location in South Africa: the Barberton Greenstone Belt, a new UNESCO World Heritage Site.

Dr. Drabon's website: https://drabon.eps.harvard.edu

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

If you've ever wondered where the Moon came from, this the episode for you! To answer that question, we'll collect Moon rocks with Neil Armstrong, spin merry-go-rounds with Charles Darwin's son, and play planetary billiards. In the end, truth is stranger than fiction.

Extra credit: Take some time for yourself and have a good long look at the moon.

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.

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.

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.

Season 1 Premiere

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.

Our introductory trilogy on deep time ends by tackling an important question: How do we know how old the Earth is?