News — Mark Salvatore has been studying Mars’ surface for years. With NASA’s InSight mission launching, he may (relatively) soon get a chance to look much deeper. This mission, Salvatore said—the first to land on Mars since the Curiosity Rover—could clarify the timeline of Mars’ surface hardening and the end of liquid water on the surface. It also could tell planetary geologists like himself more about the seismic activity and interior structure of Earth’s closest planetary neighbor.
Salvatore is an assistant professor in the Department of Physics and Astronomy at Northern Arizona University. His research focuses on the formation and evolution of planetary surfaces using a field, lab and remote sensing techniques. Much of his field research takes place in Antarctica, which is similarly cold and dry. Salvatore also has a grant from NASA to support his work in NAU’s Mars Science Laboratory Curiosity Rover, which allows him to collaborate with scientists, engineers and NASA’s rover operators to guide the Curiosity around Mars.
Expert: Mark Salvatore, assistant professor of astronomy; (928) 523-0324 or [email protected]
- Significance of the mission: The mission will provide the clearest "look" into the interior structure of Mars, leading to a better understanding of the thickness and structure of the martian core, mantle and crust. Operating seismometers that have detected seismic activity have only been deployed on the Earth and the moon (the Mars Viking landers in the 1970s had seismometers, but there were numerous issues that led to inconclusive results). Because Mars is intermediate in size between the Earth and the moon, understanding the internal structure of this intermediate rocky planet will help us to understand planetary formation and differentiation processes.
- Meaning for further research: Future research will benefit from this improved understanding as it can potentially clarify when the molten outer core of Mars solidified, destroying the magnetic field and leading to global environmental changes as the atmosphere was stripped away by the solar wind. As a scientist interested in the martian surface and environment, this aspect is of particular interest to me. The stripping of the martian atmosphere almost certainly coincides with the end of liquid water on the martian surface, so this information can place important constraints on the timing of martian surface processes and surface habitability.
- What scientists are hoping to find: Seismic activity can originate in a few different ways on planetary surfaces. First (and most exciting) would be "marsquakes," where internal stresses within the crust lead to the equivalent of martian earthquakes. This deep seismicity (originating many kilometers below the surface) can propagate seismic waves to a great depth and provide information about the internal structure of the planet. The second source of seismicity is meteorite impacts, which are concentrated at the surface but provide similar seismic information. By interpreting these signals and feeding them into detailed models of the interior structure of the planet, scientists can learn quite a bit about what subsurface properties must be present to reproduce these signals.
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