Dawn Spacecraft Still Orbiting Ceres

The Dawn spacecraft has been in orbit around Ceres for more than a year now (it doesn’t seem like it’s been than long), and has been in its penultimate “close up” orbit (385km) for a couple of months. This pass is yielding very high resolution imagery, which are being reported this spring.

There is far too much coming out for me to keep track. The summaries indicate that there is water ice on Ceres, which by now is not surprise. We have found water everywhere in the solar system. In the case of Ceres, this is suggested by studies of Gamma ray interactions with the surface, which indicate a lot of Hydrogen present, and hence, probably water ice. (Note to self: find the actual research reports when they are available.)

The much hyped “bright spot” at Occator Crater became two as Dawn closed in, and now has resolved in to many bright spots. Other images show similar but smaller bright spots at other craters.

Occator Crater. The images used to make these mosaics were taken from Dawn’s low-altitude mapping orbit (LAMO), 240 miles (385 kilometers) above Ceres. NASA

It is also apparent that the over hyped “bright spots” are seen all over Ceres, especially where craters have disturbed the surface. Current thinking is that they are magnesium sulphate (Epsom salts) left behind when salty water splashed onto the surface by the impact quickly evaporated, leaving behind salt flats.

The evolution of the “bright spot” is a great illustration of the payoff from close up observations.  All the theorizing in the world (not to mention the idiotic “guessing game” NASA put on the web) are useless unless we have solid data.  And the data is so much better if we actually go there and measure it.

 

 

Space Saturday

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