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Project Progress

Ice exists in sublimation environments on many planetary surfaces, including Mars, Antarctica, and possibly the polar regions of the Moon. Schorghofer and Edgett (2005) studied observations of seasonal ice at unusually low latitudes on Mars, where it exists on cold pole-facing slopes (Figure 1).

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Although we determined that the observed frost patches consist of CO₂ rather than H₂O ice, the implication is that seasonal water frost exists near equatorial latitudes on Mars. Another study we have completed (Schorghofer, 2005) concerns ground ice in Beacon Valley, Antarctica. Radiometric dating suggests the ice is at least 8 million years old and ranks as the oldest ice ever found on Earth. This age was thought to be incompatible with the theoretical rate of sublimation loss. Our analysis of diffusion processes and meteorological data identified a mechanism by which ground ice can survive indefinitely (Figure 2).

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We have also spent a great deal of time planning and designing laboratory experiments in sublimation environments, which should eventually bring together astronomy and biology. A grant proposal has been submitted to NASA-MFR and, with existing equipment and external seed funding, we have recently purchased the first components for preliminary experiments. The envisioned apparatus will simulate lunar, martian, and antarctic temperature and pressure conditions and will be used not only to study ices in sublimation and near-melting environments, but also biological processes, including migration and dispersal of organic material.