Earth’s Geologic History Explained — Eons, Eras, Mass Extinctions, and the Rise of Humans | Chapter 13 from Earth: Portrait of a Planet
Earth’s Geologic History Explained — Eons, Eras, Mass Extinctions, and the Rise of Humans | Chapter 13 from Earth: Portrait of a Planet How did our planet transform from a molten world to a home for complex life and human civilization? Chapter 13 of Earth: Portrait of a Planet by Stephen Marshak presents the dramatic biography of Earth—spanning 4.56 billion years of geologic evolution, mass extinctions, and the rise of life. For a full podcast summary, watch the chapter video on YouTube , or read below for a detailed timeline and key insights. Hadean Eon: Earth’s Violent Beginnings The Hadean marks Earth’s formation 4.56 billion years ago, featuring a molten surface, intense bombardment, and the impact that created the Moon. Early magma oceans cooled, the first atmosphere formed, and water condensed to make oceans. Archean Eon: Birth of Continents and Life During the Archean (4.0–2.5 Ga), crustal rocks and protocontinents developed. The first oceans appeared, and life bega...