Atmospheres as Habitats

Area of Science:

• Astrobiology
• Planetary Science
• Origin of Life Research

Background:

• Planetary atmospheres offer essential resources for life but pose significant survival challenges.
• The potential for atmospheric habitats, independent or symbiotic with surface biospheres, is largely unexplored.
• Airborne life represents a novel frontier in the search for extraterrestrial life.

Purpose of the Study:

• To evaluate the underappreciated potential of planetary atmospheres as habitats for life.
• To introduce four key hypotheses regarding the existence and study of airborne life.
• To highlight the need for new theoretical, observational, and experimental approaches in astrobiology.

Main Methods:

• Review of existing knowledge on atmospheric habitability.
• Formulation of hypotheses concerning airborne life (H-I to H-IV).
• Identification of research gaps in atmospheric life detection.

Main Results:

• Planetary atmospheres provide fundamental requirements for life but also present unique challenges.
• Four hypotheses propose the possibility of airborne life on Earth, in the lab, within our solar system (Venus), and on exoplanets.
• Current understanding is insufficient to confirm or deny multigenerational airborne life on Earth.

Conclusions:

• Atmospheric habitats warrant further investigation for their astrobiological significance.
• Venus and exoplanetary atmospheres are potential targets for future aerobiosphere assessments.
• Advancing the study of airborne life requires interdisciplinary theoretical, modeling, observational, and experimental efforts.