On a recent episode of SETI Live, host Beth Johnson spoke with Dr. Anastasia Yanchilina, the first recipient of the SETI Institute’s Frank Drake Postdoctoral Fellowship. Their conversation explored a central issue in astrobiology: how to distinguish genuine biosignatures from abiotic processes that only mimic life.

Dr. Yanchilina’s research blends planetary science with laboratory studies, focusing on icy moons such as Europa and Enceladus, thought to conceal subsurface oceans. In her Caltech lab, she creates “chemical gardens,” mineral structures that form when metal salts react in alkaline solutions. These self-assembled, plant-like tubes resemble biological membranes and transport fluids through osmosis, yet they are entirely nonliving. Recognizing such false positives is crucial for interpreting data from ocean worlds.

On Earth, hydrothermal vents generate mineral chimneys that not only resemble chemical gardens but also host microbial ecosystems. Both environments feature chemical gradients and compartmentalization, conditions that may have supported life’s origins and could exist elsewhere in the solar system. Dr. Yanchilina extends her experiments by testing factors such as high alkalinity (pH ~11), the presence of amino acids, and ultraviolet radiation, simulating early Earth and extraterrestrial conditions. These studies ask whether abiotic structures can foster increasingly complex, prebiotic molecules.

To separate biology from chemistry, she emphasizes isotopic fractionation, where organisms favor lighter isotopes, and chirality, as life exclusively uses left-handed amino acids and right-handed sugars. Such markers, integrated into future missions, could confirm whether organic compounds are biological.

Her work also highlights the difficulty of defining life, suggesting it may be better viewed as an evolving process rather than a fixed category. Future steps include isotope analysis, testing microbial interactions with mineral structures, and simulating diverse planetary environments.

Scientist looks forward to missions such as Europa Clipper, Dragonfly and Mars Life Explorer, which will carry advanced instruments to measure isotopes and chirality. By recreating extraterrestrial conditions in the lab, her fellowship sharpens the tools needed to identify life beyond Earth.

For more details, read the article by SETI Institute.