143 - Andrew Knoll: The Origins of Life on Earth

Andrew Knoll is the Fisher Professor of Natural History in the Department of Earth and Planetary Sciences at Harvard University. Andy’s work straddles the line between the early evolution of life on Earth and our planet’s environmental history. He has written numerous books on these subjects, most recently A Brief History of Earth: Four Billion Years in Eight Chapters (Custom House). In this episode, Robinson and Andy discuss when and how life arose on earth—and, just as importantly, what and how we know about it. Then they turn to some related topics, such as the diversity of microbial life on Earth and how it shaped our environment. They finish off with the possibility of life on Mars, as Andy was part of NASA’s MER mission to Mars, which examined the soil and geology of Mars’s surface through two rovers, Spirit and Opportunity. A Brief History of Earth: https://a.co/d/dLrMhVz OUTLINE 00:00 In This Episode… 00:51 Introduction 03:23 On Walt Whitman and The Learn’d Astronomer 11:36 Big Numbers Concerning Life and the Age of the Universe 29:47 On The Earliest Life on Earth 46:29 How Did Life Begin? 58:21 How Far Back Can We Trace Humans on the Tree of Life? 01:08:42 The Diversity of Microbial Life 01:19:43 The Branching of the Tree of Life 01:24:08 How Did Microbes Shape Our Atmosphere? 01:34:48 What Does Martian Soil Tell Us About The Life That Might Be Found There? Robinson’s Website: http://robinsonerhardt.com Robinson Erhardt researches symbolic logic and the foundations of mathematics at Stanford University. Join him in conversations with philosophers, scientists, weightlifters, artists, and everyone in-between.