Earth 4D: Subsurface Science & Exploration
Beneath our feet is a vast, unexplored world consisting of tens of kilometres of thick crust containing water, gases, nutrients, resources, and various forms of life. The Earth 4D program’s multidisciplinary team draws on geology, chemistry, planetary science, and engineering to investigate the interactions between the subsurface and the surface on Earth. They seek to inform and expand our understanding of planetary evolution and the possibility of finding life elsewhere.
RESEARCH AND SOCIETAL IMPACT HIGHLIGHTS
Surveillance innovation and the distribution of resources and opportunities
Several program members provided important direction and input into the National Academies of Sciences, Engineering, and Medicine’s report Origins, Worlds, and Life: A Decadal Strategy for Planetary Science and Astrobiology 2023-2032. This planning and policy document sets the 10-year plan and priorities for NASA research and missions, and formulates a community consensus about the most compelling scientific questions in the field for the decade ahead.
Embracing a spectrum in the search for life beyond Earth
In the search for life beyond Earth, distinguishing between living and non-living is difficult. Suggested by Earth 4D Fellow Heather Graham (NASA Goddard Space Flight Center) and Program Co-Director Barbara Sherwood Lollar (University of Toronto), a more inclusive representation in the search for extracellular life could be to recognize a spectrum, or “grayness”, in what could be considered life on other planets.
As the origin of life is not a singular event, and, hindered by making comparisons of what life is on Earth, researchers may miss clues in identifying potential life elsewhere. By recognizing the limitations posed by grayness, life detection researchers will be better able to develop methods sensitive to prebiotic chemical systems and life with alternative biochemistries.
Digging deeper to explore ancient waters
Underground water aquifers have the potential to serve as both a valuable source of scientific insight into the Earth’s past and a potential source of risk for today’s subsurface activities. Program Co-Directors John Mustard (Brown University) and Barbara Sherwood Lollar, along with Fellows Jennifer McIntosh (University of Arizona), Christopher Ballentine (University of Oxford), Joseph Michalski (University of Hong Kong), Advisor Jeffrey McDonnell (University of Saskatchewan), and their trainees and collaborators, critically evaluated the extent of groundwater two to ten kilometres below our feet, and assessed the water volumes to be greater than that of ice sheets. Accurate estimates of aquifer volume and connectivity are necessary for safely planning subsurface activities such as hydrogen production, nuclear waste storage, and carbon sequestration. These ancient waters may also support microbial ecosystems still active today, knowledge about which could inform mission planning for exploring potentially habitable zones elsewhere in the solar system.
Bringing experts and researchers together to discuss life on Mars
In collaboration with the International Space Science Institute (ISSI) in Switzerland, Program Co-Directors John Mustard and Barbara Sherwood Lollar organized a two-day virtual workshop in October 2021. Convening international academic and space agency researchers, the group discussed the scientific, technological, and mission requirements for finding extant subsurface life on Mars. This virtual meeting laid the groundwork for a series of in-person workshops with the ISSI.
Path to Societal Impact
We invite experts in industry, civil society, healthcare and government to join fellows in our Earth 4D: Subsurface Science & Exploration program for in-depth, cross-sectoral conversations that drive change and innovation.
Experts from academia, industry, and international space agencies and CIFAR fellows in the Earth 4D program are developing the science, technology, and requirements for Mars missions to understand the limits of habitability.
Areas of focus:
- Accessing information about water kilometres under the surface of planets, both in our own solar system and elsewhere
- Developing international mission architectures for subsurface Mars exploration
Earth & Planetary Sciences
Geochemistry, including isotope geochemistry and bio-geochemistry
Planetary and environmental modelling
Fellows & Advisors
CIFAR Azrieli Global Scholars
Earth 4D: Subsurface Science and Exploration
New modelling by Earth 4D researchers quantifies salty water reservoirs.October 01, 2021
Earth 4D: Subsurface Science and Exploration
She is making sure we can trust future claims of alien life by thinking about how life forms might evolve differently on...February 03, 2021
University of Toronto geochemist is the 2019 recipient of the Gerhard Herzberg Canada Gold Medal for Science and Enginee...May 06, 2019
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