New Rosetta view of the comet - and a comparison to other comets
Posted by Emily Lakdawalla
31-07-2014 15:02 CDT
Rosetta's view of Churyumov-Gerasimenko is getting better and better. Today they released a new image from the high-resolution OSIRIS camera, and it's a very fresh one, taken only two days ago. Distinct features are coming into view. I'm curious about the black dot on the duck's back -- it reminds me of the black boulder (PDF) that Hayabusa saw on Itokawa.
This is finally a detailed enough image for me to update my "comets visited by spacecraft" montage! I'll probably re-update this again with a better image in the future, but it's good enough for now. (Visit planetary.org/cometscale to see if there's a newer version -- that link will return you to this post now, but if I update the image again I'll make it go to the updated one.) Notice that of six comets that we've visited, at least four of them seem to consist of two (or more) bodies welded together with a narrow neck in between. There's the Borrelly bowling pin, the Hartley 2 dog bone, Halley's dumbbell, and now Churyumov-Gerasimenko's duck, making double-lobed bodies more common among the comets we've visited than the marginally rounder shapes of Tempel 1 or Wild 2.
The Rosetta image looks a little weird in this composite because Rosetta is approaching the comet from the direction of the Sun, so it's equally lit all over; there's no cast shadows, no shape discernible from shading. Eventually there should be some Rosetta pictures of the comet whose lighting geometry matches the other photos better, and I'll put out a new version then!