Biosignatures of the Earth

Patty, C. H. Lucas; Kühn, Jonas G.; Lambrev, Petar H.; Spadaccia, Stefano; Hoeijmakers, H. Jens; Keller, Christoph; Mulder, Willeke; Pallichadath, Vidhya; Poch, Olivier; Snik, Frans; Stam, Daphne M.; Pommerol, Antoine; Demory, Brice-Olivier (2021). Biosignatures of the Earth. Astronomy and astrophysics, 651, A68. EDP Sciences 10.1051/0004-6361/202140845

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ontext. Homochirality is a generic and unique property of life on Earth and is considered a universal and agnostic biosignature. Homochirality induces fractional circular polarization in the incident light that it reflects. Because this circularly polarized light can be sensed remotely, it can be one of the most compelling candidate biosignatures in life detection missions. While there are also other sources of circular polarization, these result in spectrally flat signals with lower magnitude. Additionally, circular polarization can be a valuable tool in Earth remote sensing because the circular polarization signal directly relates to vegetation physiology.

Aims. While high-quality circular polarization measurements can be obtained in the laboratory and under semi-static conditions in the field, there has been a significant gap to more realistic remote sensing conditions.

Methods. In this study, we present sensitive circular spectropolarimetric measurements of various landscape elements taken from a fast-moving helicopter.

Results. We demonstrate that during flight, within mere seconds of measurements, we can differentiate (S∕N > 5) between grass fields, forests, and abiotic urban areas. Importantly, we show that with only nonzero circular polarization as a discriminant, photosynthetic organisms can even be measured in lakes.

Conclusions. Circular spectropolarimetry can be a powerful technique to detect life beyond Earth, and we emphasize the potential of utilizing circular spectropolarimetry as a remote sensing tool to characterize and monitor in detail the vegetation physiology and terrain features of Earth itself.

Item Type:

Journal Article (Original Article)

Division/Institute:

08 Faculty of Science > Physics Institute > Space Research and Planetary Sciences
08 Faculty of Science > Physics Institute
10 Strategic Research Centers > Center for Space and Habitability (CSH)
08 Faculty of Science > Physics Institute > NCCR PlanetS

UniBE Contributor:

Patty, C. H. Lucas; Kühn, Jonas Guillaume; Spadaccia, Stefano; Pommerol, Antoine and Demory, Brice-Olivier

Subjects:

500 Science > 520 Astronomy
600 Technology > 620 Engineering
500 Science > 530 Physics

ISSN:

0004-6361

Publisher:

EDP Sciences

Language:

English

Submitter:

Dora Ursula Zimmerer

Date Deposited:

10 Aug 2021 10:44

Last Modified:

14 Sep 2021 08:01

Publisher DOI:

10.1051/0004-6361/202140845

BORIS DOI:

10.48350/157949

URI:

https://boris.unibe.ch/id/eprint/157949

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