Goal 8
Determine how to recognize signatures of
life on other worlds and on early Earth.
Define and learn how to measure biosignatures that indicate the existence of past or present life in earthly and extraterrestrial samples, including remotely measured planetary atmospheres and surfaces, samples measured in situ, and samples returned to Earth for study.
Biosignatures must be identified that can reveal and characterize past or present life in earthly and extraterrestrial samples, including remotely measured planetary atmospheres and surfaces, samples measured in situ, and returned samples studied in laboratories on Earth. Our concepts of life and biosignatures are inextricably linked. To be useful for exploration, biosignatures must be defined in terms that can be measured and quantified. Measurable attributes of life include its complex physical and chemical structures and also its utilization of free energy and the production of biomass and wastes; phenomena that can be sustained through self-replication and evolution. Habitable planets create nonbiological features that mimic biosignatures and therefore must be understood in order to clarify our interpretations. We must create a library of biosignatures and their nonbiological mimics, for life as we know it. We must develop a strategy for recognizing novel biosignatures. This strategy must accommodate a diversity of biota and habitable conditions in the universe that probably exceeds the diversity observed on Earth.
- Objective 8.1—Identify
biosignatures to be sought in Solar System materials. Learn
how to recognize and interpret biosignatures which, if identified in
samples from ancient rocks on Earth or from other planets, can help
to detect and/or characterize ancient and/or present-day life.
- Objective 8.2—Identify biosignatures to be sought in nearby planetary systems. Learn how to measure biosignatures that can reveal the existence of past or present life through remote observations of distant planetary atmospheres and surfaces.