Sara Seager is an MIT astrophysicist and planetary scientist and a foundational figure in exoplanet atmospheric characterization and biosignature theory. She led the 2025 PNAS perspective src-jwst-biosignature-prospects-2025 arguing that jwst cannot definitively confirm a biosignature gas detection and that the field must accept “parallel interpretations” of ambiguous spectra until the next generation of observatories — notably the habitable-worlds-observatory and LIFE — come online.
Seager has long advocated for atmospheric search strategies that go beyond single-gas “silver bullets” and for integrating 3D atmospheric modeling into retrieval pipelines.
Key Positions
- Detection of biosignature gases is in principle within JWST’s reach but not confirmable.
- JWST can nominate candidate planets; only next-gen telescopes can confirm.
- Transmission spectroscopy produces 1D averages of 3D atmospheric processes — an intrinsic methodological limit.