ceres

NASA’s Dawn Spacecraft is approaching Ceres, and sending back the highest-resolution images of the planet the dwarf planet ever seen.  White patches on Ceres resemble water ice.  Ceres has no atmosphere, and exposed water ice on its surface would be expected to sublimate (evaporate directly from its frozen state) into the vacuum of space.  Therefore, it is possible that the light patches are a light-colored mineral of some kind that does not sublimate.

However, the possibility that the light patches are ice has not yet been ruled out.  On the contrary, in January of 2014, ESA’s Herschel observatory observed streams of water vapor erupting from two spots on Ceres.  If Ceres contains enough water, sublimated water vapor might condense onto colder spots of its surface under the influence of its weak gravity, maintaining water ice on the dwarf planet for a very long time.  Or Ceres may already hold enough water ice to sustain sublimation for millions of years without losing all of its ice.  Other bodies in the solar system beyond Earth are known to hold large quantities of water ice, for example Mars, Jupiter’s moon Europa, and many comets.

If Ceres turns out to be a mostly rocky body with abundant water ice, it may be a prime candidate for a future space base due to its low gravity, stable surface, and abundant water.  The only critical missing element might be carbon, which might be found on a nearby asteroid.  Perhaps science-fiction stories like Sandfort’s and Bieser’s Escape From Terra are not so far-fetched after all!