agnostic biosignature Archives - Astrobiology

Dr. Kevin Hand works with the Minos chamber at NASA JPL's Ocean Worlds Laboratory -- NASA

Astrochemistry, Biochemistry & Organic Chemistry, Biophysics, Biosignatures & Paleobiology, Imaging & Spectroscopy, Interstellar, Status Report

Detecting Fundamental Chiral Biosignatures in the Ultraviolet Polarization Spectrum

by Keith CowingMay 11, 2026May 11, 2026

Chiral molecules are ubiquitous and necessary for life as we know it. In extant life, the amino acid and sugar constituents of proteins and biopolymers consist of only one enantiomer.

Grid plot of the log-Bayes factor for the null (no life) hypothesis versus the affirmative (life) hypothesis (Kf0) when a sample of Ntot = 24 targets are split into two groups with differing life rates but a global confounder rate. Although a large zone of ambiguity persists, the life hypothesis can be strongly claimed in 40 of 169 possible outcomes. For comparison, with a monolithic population we find that no outcomes could ever achieve this. -- astro-ph.IM

Astrobiology (general), Biosignatures & Paleobiology, Habitable Zones, Status Report

The Catastrophic Consequences of Agnosticism for Life Searches and a Possible Workaroun

by Keith CowingMay 7, 2026May 7, 2026

Planned and ongoing searches for life, both biological and technological, confront an epistemic barrier concerning false positives – namely, that we don’t know what we don’t know.

The concept behind the model is simple: life can travel to and terraform planets around other stars. In doing so, the planet that life travels to becomes more similar to the planet it came from. In this example, life from a planet resembling Earth travels to a red planet. The process plays out again and again. Each time, after being terraformed, a planet becomes more "Earth-like" than would be expected from random chance, given the locations of the planets. However, the focus is not on identifying Earth-like planets. Instead, the aim is to identify any group of planets that are more similar to each other than would be expected by chance, and are localised in space. This technique is agnostic: it does not require making assumptions about habitability or passing judgment on the "kinds of planets" that are amenable to life. -- Institute of Science Tokyo

Biogeochemical Cycles & Geobiology, Biosignatures & Paleobiology, Gaia - Planetary Perspectives, Panspermia, Planetary Protection & Biosafety, Press Release, Terraforming & Geoengineering

Terraforming/Panspermia: A New Way To Detect Life Beyond Earth Without Knowing What Life Looks Like

by Keith CowingApril 16, 2026

A research team of Specially Appointed Associate Professor Harrison B. Smith of Earth-Life Science Institute (ELSI) at Institute of Science Tokyo and Specially Appointed Associate Professor Lana Sinapayen of National […]

Platinum replica electron microscope image of the inner membrane of a mammalian cell. Source: Justin Taraska, Ph.D., chief of NHLBI’s molecular and cellular imaging laboratory -- NIH.gov

Biochemistry & Organic Chemistry, Biosignatures & Paleobiology, Exploration Gear & Tech, Extremeophiles and Extreme Environments, Fossils & Paleontology, Genomics, Proteomics, Bioinformatics, Imaging & Spectroscopy, Microbiology & Virology, Origin & Evolution of Life, Status Report, Tricorders & Sensors

Membrane-Spanning Molecular Lengths as an Agnostic Biosignature

by Keith CowingMay 27, 2025May 27, 2025

We explore a hypothesis in which the detection of classes of lipid-like molecules with similar abundance-averaged lengths would constitute a biosignature for other worlds.

Target planet selection and terraformation. A. The objective function, used for determining the destination of life from a terraformed “parent” planet. Candidate destinations are first constrained by a maximum positional distance threshold; among these candidates, the planet closest in composition to the parent planet is chosen as the target. B. Simulations are initialized with 1 origin of life, causing the initial distribution of planet compositions (seen in A) to become correlated. C. An example of how we determine target planet composition when retaining 10% of the preterraformed planet composition. Note that while our simulations use a 3D space, the concept figure shows only show a 2D space for clarity. -- astro-ph.EP

Atmospheres, Climate, Weather, Biogeochemical Cycles & Geobiology, Biosignatures & Paleobiology, Gaia - Planetary Perspectives, Imaging & Spectroscopy, Panspermia, Status Report, Terraforming & Geoengineering

An Agnostic Biosignature Based on Modeling Panspermia and Terraformation

by Keith CowingApril 14, 2025March 3, 2026

A fundamental goal of astrobiology is to detect life outside of Earth. This proves to be an exceptional challenge outside of our solar system, where strong assumptions must be made […]

Energy-ordered resource stratification as an observable signature of life. (a) Stratified profiles of chemical resources layered by energy content are commonly observed on Earth, e.g., microbial mats, early Earth fossils (stromatolites), Winogradsky columns, and in marine environments. (b) Such profiles are generally understood to be shaped by biotic species (typically microbes) that metabolize these resources for energy. Here, we propose that energy-ordered resource stratification is a robust signature of biotic action. -- q-bio.PE

Biochemistry & Organic Chemistry, Biophysics, Biosignatures & Paleobiology, Status Report

Energy-ordered Resource Stratification As An Agnostic Signature Of Life

by Keith CowingApril 4, 2024April 4, 2024

The search for extraterrestrial life hinges on identifying biosignatures, often focusing on gaseous metabolic byproducts as indicators. However, most such biosignatures require assuming specific metabolic processes.