Dawn breaks over Ceres … and perhaps reveals signs of habitability

Dawn breaks over Ceres … and perhaps reveals signs of habitability

by EarthSky Voices in » Science Wire, Space
http://earthsky.org/space/dawn-breaks-over-ceres-and-perhaps-signs-of-habitability?utm_source=EarthSky+News&utm_campaign=22ee84471e-EarthSky_News&utm_medium=email&utm_term=0_c643945d79-22ee84471e-393525109

The Dawn spacecraft is about to start its investigation of Ceres. Suggestions of icy volcanism have led to speculation that the dwarf planet could potentially be habitable.

By Monica Grady, The Open University

NASA’s Dawn spacecraft is about to start its investigation of the largest member of the asteroid belt, 1 Ceres. It will take detailed images of the dwarf planet, and produce a geological map of its entire surface. But even before the spacecraft has reached its optimum orbit, the preliminary results just released are already surprising and delighting planetary scientists.

Up until February 2015, the best images taken of Ceres were from the Hubble space telescope, showing a near-spherical body with one area that was much brighter than the rest of the surface. As Dawn approached Ceres, its camera acquired some remarkable images, at about three times the resolution of those from Hubble. The pictures verified that there was indeed a brighter region.

Even better, close examination of the images showed that the area varied in brightness over the course of Ceres’ day (which is only about nine hours long), growing dimmer as the dwarf planet moved into darkness. It is interpretation of this variability that has planetary scientists buzzing.

As if that were not enough, a further series of pictures appear to show a plume emanating from the surface. Is Ceres active? Does it have a layer of water or ice below a thin crust of rock? Could it be a ball of mud, overlain by a muddy ocean, on top of which is another thin muddy crust? The exact structure of Ceres is not yet known, although it is clear that it’s not rocky all the way through – its density is too low, so there must be at least some water or ice present.

Suggestions at the 46th Lunar and Planetary Science Conference in Houston, Texas, of icy volcanism on Ceres have led to speculation that the dwarf planet could potentially be habitable. Although Ceres does not have an atmosphere, life might exist in a subsurface ocean, as has been suggested for Europa or Enceladus, moons orbiting Jupiter and Saturn respectively.

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This article was originally published on The Conversation.
Read the original article:
http://theconversation.com/dawn-breaks-over-distant-ceres-and-perhaps-signs-of-habitability-38967