Color Catalogue of Life in Ice: Surface Biosignatures on Icy Worlds
Bibliographic record
Abstract
Abstract: With thousands of discovered planets orbiting other stars and new missions that will explore our solar system, the search for life in the universe has entered a new era. However, a reference database to enable our search for life on the surface of icy exoplanets and exomoons by using records from Earth’s icy biota is missing. Therefore, we developed a spectra catalogue of life in ice to facilitate the search for extraterrestrial signs of life. We measured the reflection spectra of 80 microorganisms—with a wide range of pigments—isolated from ice and water. We show that carotenoid signatures are wide-ranged and intriguing signs of life. Our measurements allow for the identification of such surface life on icy extraterrestrial environments in preparation for observations with the upcoming ground- and space-based telescopes. Dried samples reveal even higher reflectance, which suggests that signatures of surface biota could be more intense on exoplanets and moons that are drier than Earth or on environments like Titan where potential life-forms may use a different solvent. Our spectral library covers the visible to near-infrared and is available online. It provides a guide for the search for surface life on icy worlds based on biota from Earth’s icy environments. Research Article: https://doi.org/10.1089/ast.2021.0008 Email: ligiacoelho@tecnico.ulisboa.pt Calibrated Data - Folders organized by sample Filenames key: {month}.{day}.{sample identifier}.{dryness}.cal.txt For sample dryness "f" stands for "fresh", measurement was collected while the sample was still wet from preparation. "w" stands for "week", measurement was collected after a week of drying time. "cal" identifies that the data has been calibrated as described in the methods section of the linked article and results section of Hegde et al. (2015). Raw Data - Folders organized by sample Filenames key: {month}.{day}.{sample identifier}.{dryness}.B.txt For sample dryness "f" stands for "fresh", measurement was collected while the sample was still wet from preparation. "w" stands for "week", measurement was collected after a week of drying time. "B" identifies the black background used during sample measurement which is calibrated for using data in the Reference Data folder. Reference Data - Folders organized by reference type Controls - calibrated control samples same filename format as calibrated data. Blank sample, fresh (f) and week old (w), with a black background. DarkReference - Measurements of the dark background used to hold samples. No sample, black background only. LightTrap - Measurement of the light trap. No background. TargetReference - Service file for the white reference used. WhiteReference - White reference measurements by date. White reference only. Affiliations Centro de Química Estrutural, Departamento de Engenharia Química, Instituto Superior Técnico, Universidade de Lisboa, Lisboa, Portugal. Institute for Bioengineering and Biosciences, Instituto Superior Técnico, Universidade de Lisboa, Lisboa, Portugal. Department of Astronomy, Cornell University, Ithaca, New York, USA. Carl Sagan Institute, Ithaca, New York, USA. Department of Microbiology, Cornell University, Ithaca, New York, USA. School of Civil and Environmental Engineering, Cornell University, Ithaca, New York, USA. Landscape, Environment, Agriculture and Food—LEAF Centre, Instituto Superior de Agronomia, Universidade de Lisboa, Lisboa, Portugal. Centre for Northern Studies (CEN), Takuvik & Biology Department, Université Laval, Québec, Canada.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.001 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.009 | 0.006 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.000 | 0.001 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.010 | 0.006 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".