StarTalk Radio How Did Life Begin? with Betül Kaçar
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May 5, 2026 
Betül Kaçar, an astrobiologist and professor who directs NASA-funded research on metal use and early life, joins to explore life’s origins. Short, lively conversations cover resurrecting ancient enzymes in the lab, microbes’ outsized role on Earth, how metabolic energy drives habitability, nitrogen fixation’s rarity, and what biosignatures might reveal about life beyond our planet.
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Talking To Extinct Biochemistry In The Lab
- Kaçar likens resurrecting ancient enzymes to bringing an extinct language back and forcing microbes to 'speak' it.
- She describes cloning inferred ancient DNA into microbes to have a lab 'conversation' with past biochemistry.
Evolutionary Singularities Shaped Earth's Trajectory
- Some major biological innovations appear as evolutionary singularities that happened only once and reshaped Earth.
- Kaçar cites origin of life, oxygenic photosynthesis, and nitrogen fixation as rare one-off transitions with planet-scale impact.
Nitrogen Fixation Is An Ancient Energy Breakthrough
- Biological nitrogen fixation solved an energetic chemistry problem by evolving an enzyme to break N2's triple bond.
- Kaçar notes nitrogen fixation arose ~3 billion years ago and modern industry (Haber-Bosch) consumes ~2% of global energy to mimic it.
