The Science of Everything Podcast Episode 157: The Geologic Time Scale
Jan 17, 2026
Dive into Earth's history as the podcast explores the geologic timescale! Discover how 'golden spikes' define eras and learn about pivotal events like the Great Oxidation Event and the rise of eukaryotes. Unravel the mysteries of the Cambrian explosion, examine the supercontinent cycle, and understand the significance of mass extinctions throughout time. From the formation of continents to the emergence of complex life, this journey through geological epochs is both enlightening and entertaining!
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Phanerozoic Marks Complex Life
- The Phanerozoic Eon (last ~540 million years) is when macroscopic animal and plant life became common on Earth.
- Most familiar fossils and complex ecosystems come from this relatively recent slice of geological time.
Life Emerged Very Early
- The Hadean began at Earth's formation ~4.6 billion years ago and ends near 4 billion years ago with the oldest rocks.
- Life likely emerged at the end of the Hadean in shallow ocean geothermal environments.
Great Oxidation Reshaped Life
- The Great Oxidation Event (~2.5 billion years ago) raised atmospheric O2 and reshaped the biosphere.
- That oxygenation likely caused a major die-off of anaerobic microbial life and opened niches for new organisms.