Cool Worlds Podcast #22 Sara Walker - Origin of Life, Assembly Theory, Biosignatures
May 18, 2025
Sara Walker, a leading Professor of Earth & Space Exploration at Arizona State University, introduces her groundbreaking assembly theory in astrobiology. She discusses the complexities of life's origins as a continuous process rather than a single event, emphasizing the role of prebiotic chemistry. Walker explains how assembly theory can help identify potential biosignatures on other planets, revolutionizing the search for extraterrestrial life. The conversation also touches on the philosophical implications of evolution and complexity in the universe.
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Origin As Cascading Evolutionary Transitions
- The origin of life is better framed as a cascade of evolutionary transitions, not a single 'first' event.
- Post-selecting on final cellular products biases experiments and hides the role of emergent selection.
Planet As A Combinatorial Search Engine
- View a planet as a combinatorial search engine exploring chemical space via many microenvironments.
- Planetary-scale mixing and interaction are necessary because chemical space is vastly larger than any single niche can exhaustively explore.
Standardize Experiments To Measure True Novelty
- Standardize prebiotic experiments by measuring complexity of inputs and outputs and quantifying human selection in protocols.
- Use those bounds to estimate how much complexity chemistry generates without biological help.
