Earth 4D - Subsurface Science and Exploration

Three thematic and integrated Research Topics and related questions are at the heart of this challenge and will form the basis for the proposed program and define the dynamics of its initial and future membership. Topic I. What are the physical and chemical controls on planetary Subsurface Architecture that determine the storage, transport and interaction of fluids and gases in the interiors of Earth, and other planets and moons in our universe? How do these systems dynamically respond over space and time and what are the implications for the habitability of the subsurface, the sustenance and preservation of life, and the interactions between the subsurface and surface hydrosphere? Over deep time how might these connections have changed and how will they change in the future in response to planetary evolution and to climate change? Topic II. What are the known and unknowns about the origin, evolution and dispersal of Subsurface Life (microbial, viral and multi-cellular) compared to the surface biosphere? What controls the boundaries of different biomes in the subsurface and the interaction of the subsurface biosphere with surface life? Is the presence of life on a planet dependent on specific planetary architectures explored in Topic I, or are there a range of different “habitability models” that might predict where life is possible – both on Earth and off? Topic III. What are the transformational models of Subsurface Energy systems required to evaluate and assess the competing challenges of traditional energy resources, unconventional and renewable energy systems, novel subsurface resources, and stewardship of the subsurface environment and water resources essential for life? How does this knowledge transform our understanding of the Earth’s global energetic capacity to sustain life? How do these new models and perspectives inform our understanding of planetary science and the search for life in the solar system and beyond?