The Nexus for Exoplanet System Science (NExSS) is a NASA research coordination network dedicated to the study of planetary habitability. The goals of NExSS are to investigate the diversity of exoplanets and to learn how their history, geology, and climate interact to create the conditions for life. NExSS investigators also strive to put planets into an architectural context -- as solar systems built over the eons through dynamical processes and sculpted by stars. Based on our understanding of our own solar system and habitable planet Earth, researchers in the network aim to identify where habitable niches are most likely to occur, which planets are most likely to be habitable. Leveraging current NASA investments in research and missions, NExSS will accelerate the discovery and characterization of other potentially life-bearing worlds in the galaxy, using a systems science approach.
The study of exoplanets is a relatively new field that emerged in the 1990's with the discovery of the hot Jupiters like 51 Peg b. Giant planets dominated the landscape of new discoveries for more than a decade until NASA’s Kepler Mission lifted our blinders to the terrestrial-sized planets populating the galaxy. From Kepler, we've learned that the Milky Way may be home to billions of earth-sized planets orbiting in the habitable zone of their host stars. With this knowledge, the possibility of finding life beyond Earth looms dramatically larger on the horizon. NExSS grew from this realization.
NExSS also grew out of the recognition that a synthesized approach that draws on expertise from many fields is required to maximize the information from these discoveries and accelerate future progress. The key to this effort is understanding how biology interacts with the atmosphere, geology, oceans, and interior of a planet, and how these interactions are affected by the host star. This “systems science” approach will help scientists better understand how to look for life on exoplanets.
To accomplish this, NASA created a framework for an unprecedented collaboration among the four science communities supported by NASA’s Science Mission Directorate:
- Earth scientists developed the systems science approach by studying our home planet as a coupled atmosphere-hydrosphere-cryosphere-geosphere-biosphere system. Earth is our most accessible and best-characterized planet and can serve as a laboratory for the investigation of other habitable planets.
- Heliophysicists add another layer to this systems science approach, by studying the properties of the Sun (and other stars) and looking in detail at how they interact with the magnetic fields and climates of their orbiting planets.
- Planetary scientists apply systems science to the wide variety of worlds within our solar system. Detailed information from a sampling of planets with exotic landscapes will broaden our perspective and can be used to inform theoretical models that can be applied to exoplanets.
- Astrophysicists collect data that reveal the diversity of planets in the galaxy and the properties of their host stars. These data are used to model how solar systems form and evolve.
NExSS will bring together these prominent research communities in an unprecedented collaboration. NExSS will explore the most effective means to communicate and share varied (sometimes disparate) perspectives and approaches to research questions. Participants will work together to classify the diversity of newly discovered exoplanets, understand the potential habitability of these worlds, and develop tools and technologies needed in the search for life beyond Earth. Teams will seek approaches that best facilitate community engagement and collaborative research efforts. NExSS will also promote training and educational activities across disciplinary, organizational, divisional, and geographic boundaries.
NExSS will play a role in elevating the visibility and priority of exoplanet science research. It will broaden the opportunities for scientists in the U.S. to engage in this type of interdisciplinary research, strengthen collaborations with the international community of scientists involved in similar research, and build support for future exoplanet missions and studies - all in the pursuit of the answer to one of humanity’s oldest questions: Are we alone?