Study of the origin, evolution, and distribution of life in the universe — habitability, biosignatures, extremophiles, prebiotic chemistry. Active NASA-funded interdisciplinary field at the intersection of biology, chemistry, and planetary…
astrobiology
Habitable zone
Orbital region around a star where surface liquid water is possible on a rocky planet given plausible atmospheric CO₂. For a Sun-like star,…
Biosignature
Observable feature (chemical, morphological, isotopic, spectral) whose presence is a plausible indicator of life. Atmospheric: O₂/O₃ + CH₄…
Extremophile
Organism thriving in 'extreme' conditions by Earth norms: thermophile >60°C (Pyrolobus fumarii at 113°C), psychrophile <15°C, halophile…
Abiogenesis hypotheses
Classes: primordial soup (Miller–Urey 1953); RNA world (self-replicating ribozymes); metabolism-first (acetyl-CoA / hydrothermal-vent…
Mars habitability
Evidence of past liquid water (Gale crater lake-bed sediments, Jezero delta); sub-surface radar signatures of brines; methane detections…
Europa/Enceladus ocean worlds
Icy-shell moons with sub-surface liquid-water oceans inferred from induced magnetic fields (Europa) and active plumes (Enceladus).…
Drake equation
N = R* · f_p · n_e · f_l · f_i · f_c · L: expected number of communicating civilisations in our Galaxy as a product of astrophysical (R*,…
Fermi paradox
Given Galaxy's age (~13 Gy) and likely prevalence of habitable worlds, why is there no observable evidence of extraterrestrial…