Introductions all around- the podcast, the period of time we’ll be exploring, and the host. We’ll start by scaling Earth’s entire history down to a manageable 365 days.

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

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

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.

How did the Earth transform simple carbon into the complex ingredients of life?

Today, we'll meet a troubled Charles Darwin hunting for fossils, we'll create slime from thin air in one of the greatest laboratory experiments, and we'll learn what was in Earth's earliest atmosphere.

Extra Credit: Breathe in, breathe out, and have a sip of your favorite soup.

How old is the oldest rock, where was it found, and what type of rock is it?

To answer that question, we'll journey into Canada's Northwest Territories, deep underground to the breaking point of rocks, and we'll run into a shrimpy friend from Episode 10.

What's the next step after the oldest rock on Earth?

Today, we'll move the story forward 200 million years and 1,000 miles.

The time: 3.8 billion years ago... or maybe much older (March 3 on the Earth Calendar).

The place: Nuvvuagittuq (noo-voo-ah-git-took), Quebec, Canada, in the lands of the Inuit.

In this episode, we'll learn how this seaside outcrop was found and the ongoing debate about its' exact age. Depending on who you talk to, these are either the second-oldest rocks on Earth, or almost as old as the Earth itself.

What is the oldest major slice of rock, one that's relatively well-preserved, one that's fueled a half-century of research?

The episode's name kinda gives it away, but stay tuned as we meet the last location of Season 2: a series of rocks near Greenland's capital. Along the way, we'll meet the different groups of people who have settled on this remote island, and a geologist from the other side of the world. I'll also take a brief detour into why I unfortunately can't talk about every single ancient rock out there.

Extra Credit: Find a choir to sing in, or play some ping-pong.

Why are some ancient rocks well-preserved, while others are extremely messed up?

Today, we'll take a side quest from our Greenland arc to learn more about metamorphosis, which changes rocks beneath our feet. On the way, we'll transform toast into cookies, take an elevator ride deep into the crust, and meet an ancient rock with a babyface.

Extra credit: make some toast, or go looking for butterflies.