My guest today is Dr. Joti Rouillard, a research fellow at the University of Science and Technology in Hefei, China. Dr. Rouillard talks about his research on the earliest fossils on Earth, microscopic bacteria 3.5 billion years old. It turns out, identifying a fossil bacteria is extremely difficult since they resemble other tiny non-living objects. We also talk about working in the Australian Outback, kangaroo encounters, and what happens when you mix alcohol and rocks.

Dr. Rouillard's email: joti.rouillard@gmail.com

Miniseries Episode 2

Australia is one of the top destinations for people who love the ancient Earth. Today, we take a brief tour around the three oldest regions in Australia: the Yilgarn Craton near Perth, the Pilbara Craton near Port Hedland, and the Gawler Craton near Adelaide. On the way, we'll meet the oldest minerals, the oldest fossils, and learn the connection between ancient bacteria and modern steel.

Miniseries Episode 3

Africa is a continent with many different nations and rocks. Today, we learn how most of Africa was fused together billions of years ago, and which pockets preserve the best evidence for ancient life (South Africa, Zimbabwe). Along the way, we'll meet the richest human in history, a giant knife made from magma, and a two-billion-year family reunion.

Miniseries Episode 5:

Asia is the largest continent, and has a lot of ancient rocks to share with the world. Today, we learn how to map a hidden continent using magnets, how copper forms in undersea castles, and how the Himalayas were born.

Many folks have claimed to find Earth's oldest fossils in the Greenland rocks, 3.7 billion years old. Before we meet and judge these contenders, we need to learn what counts as a fossil. This early in Earth history, nothing has any bones or teeth or shells, so researchers need to search for other clues. Today, I'll show you four ways to look for fossils in Earth's oldest rocks, including my personal field of study: fossilized bacteria.

Extra Credit: Find different types of organic carbon in your day, or eat a burger.

Finally, 3.7 billion years ago, we reach some of the strongest evidence for life on Earth yet. It takes a while to find, and it only looks like a few dark crystals, but it's better than anything else we've seen so far. Along the way, we'll meet three scientists who helped define the quest for Earth's oldest fossils, including one of my old bosses.

Extra Credit: Sharpen your pencils, spackle some cracks, or thank a mentor in your life.

This episode, we focus on just one special boulder from the Greenland tundra, a rock that might have Earth's oldest fossils. Over the past 10 years, scientists from around the world have used the latest technology to reveal this rock's secrets, including research published this year. What have they found?

Extra Credit: Make a time capsule or play a record.