Nikku Madhusudhan
Nikku Madhusudhan is an astronomer at the University of Cambridge who leads research on exoplanet atmospheres and biosignatures.
Key Contributions
- Hycean worlds concept: First theorized in 2021 — habitable planets entirely covered in liquid water with hydrogen-rich atmospheres, broadening the scope of exoplanet-habitability.
- K2-18b atmospheric characterization: Led the team that detected liquid water oceans, methane, and CO2 on K2-18b using jwst.
- DMS/DMDS biosignature detection: According to src-jwst-k2-18b-biosignature-2025, led the team that detected dimethyl sulfide and dimethyl disulfide in K2-18b’s atmosphere — the strongest potential biosignature ever found on an exoplanet (published April 2025, The Astrophysical Journal Letters).
Notable Quotes
“A bigger question in my mind is whether we as a species are prepared to find life as we don’t know it.”
“It’s important that we’re deeply skeptical of our own results, because it’s only by testing and testing again that we will be able to reach the point where we’re confident in them.”
2026 Status
Per src-k2-18b-technosignature-null-2026, the DMS/DMDS biosignature interpretation is now “heavily disputed” in the astrobiology community. A parallel radio technosignatures search (VLA + MeerKAT) on the same target returned a null result. Madhusudhan’s hycean world framework nonetheless remains the dominant theoretical lens for interpreting k2-18b.
sara-seager et al.’s 2025 PNAS perspective (src-jwst-biosignature-prospects-2025) treats the K2-18b DMS claim as the canonical example of the “parallel interpretations” problem: the same transmission spectrum admits hycean, mini-Neptune, and hot-magma-ocean retrievals, and JWST alone cannot arbitrate.