Does life exist on other planets, and if so, how do we know what to look for? Identifying and understanding the necessary ingredients for a planet to support life is one of NASA’s greatest science goals. By studying ways that a planet responds to its surrounding environment, SEEC researchers are pioneering methods to detect life on other worlds. For example, life on Earth has evolved with the planet’s environment, producing changes in the atmosphere called "biosignatures," telltale signs that the planet supports life. Oxygen produced through photosynthesis is considered modern Earth’s primary biosignature. Different planets may have different types of dominant biosignatures, such as biogenic methane and organic haze. In tandem with considerations of possible biosignatures, it is also critical to consider biosignature “false positive” biosignatures generated by abiotic processes to determine how to distinguish them from true signs of life.
Studies of biosignatures must consider how life both acts on and is impacted by its environment. Thanks to a diverse set of scientific expertise and cutting-edge modeling tools, SEEC research can tackle these problems from an interdisciplinary perspective, examining how possible biosignatures can be affected by a planet’s atmospheric, oceanic, climatic, stellar, geological, and biological systems. For example, biosignatures can be impacted by the star a planet orbits. Stars with different ultraviolet radiation levels will cause different chemical makeups of planets’ atmospheres, and different colors of stars could drive the evolution of different vegetation pigments on a planet’s surface.
Key Questions Guiding SEEC Research
By studying ways that biospheres interact with planetary environments, SEEC researchers are pioneering methods to detect life on other worlds.
A vast multitude of physical, chemical, and geological processes combine to produce the characteristics of a specific exoplanet’s atmosphere and surface that will be visible to future telescopes.
Planetary habitability results from a complex network of interactions between the planet, its planetary system, and host star.
In our quest to find life outside of our solar system, we look for planets that resemble Earth, the only planet that we know of that is habitable.
Earth is our only example of a planet that is habitable and inhabited, and as such represents the archetypical habitable environment for remote sensing and mission development studies.