Biosignatures & Paleobiology

Assessing Planetary Complexity and Potential Agnostic Biosignatures Using Epsilon Machines

By Keith Cowing
Status Report
February 8, 2022
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Assessing Planetary Complexity and Potential Agnostic Biosignatures Using Epsilon Machines
Statistical complexity as a function of Shannon entropy averaged across all wavelength bands for the original and synthetic Earth data.

We present a new approach to exoplanet characterisation using techniques from complexity science, with potential applications to biosignature detection.

This agnostic method makes use of the temporal variability of light reflected or emitted from a planet. We use a technique known as epsilon machine reconstruction to compute the statistical complexity, a measure of the minimal model size for time series data. We demonstrate that statistical complexity is an effective measure of the complexity of planetary features. Increasing levels of qualitative planetary complexity correlate with increases in statistical complexity and Shannon entropy, demonstrating that our approach can identify planets with the richest dynamics.

We also compare Earth time series with Jupiter data, and find that for the three wavelengths considered, Earth’s average complexity and entropy rate are approximately 50% and 43% higher than Jupiter’s, respectively. The majority of schemes for the detection of extraterrestrial life rely upon biochemical signatures and planetary context. However, it is increasingly recognised that extraterrestrial life could be very different to life on Earth. Under the hypothesis that there is a correlation between the presence of a biosphere and observable planetary complexity, our technique offers an agnostic and quantitative method for the measurement thereof.

Stuart Bartlett, Jiazheng Li, Lixiang Gu, Lana Sinapayen, Siteng Fan, Vijay Natraj, Jonathan Jiang, David Crisp, Yuk Yung

Subjects: Earth and Planetary Astrophysics (astro-ph.EP); Chaotic Dynamics (nlin.CD); Data Analysis, Statistics and Probability (
Cite as: arXiv:2202.03699 [astro-ph.EP] (or arXiv:2202.03699v1 [astro-ph.EP] for this version)
Submission history
From: Stuart Bartlett
[v1] Tue, 8 Feb 2022 07:53:13 UTC (2,020 KB)


Explorers Club Fellow, ex-NASA Space Station Payload manager/space biologist, Away Teams, Journalist, Lapsed climber, Synaesthete, Na’Vi-Jedi-Freman-Buddhist-mix, ASL, Devon Island and Everest Base Camp veteran, (he/him) 🖖🏻