New Rosetta view of the comet - and a comparison to other comets
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.
ESA / Rosetta / MPS for OSIRIS Team MPS / UPD / LAM / IAA / SSO / INTA / UPM / DASP / IDA
OSIRIS view of comet Churyumov-Gerasimenko on July 29, 2014
Rosetta obtained this view of the comet on July 29, 2014 from only 1950 kilometers away. The pixel scale is about 37 meters. This image has been enlarged by a factor of 3 from the original resolution.
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.
Image credits: Halley: Russian Academy of Sciences / Ted Stryk. Borrelly: NASA / JPL / Ted Stryk. Tempel 1 and Hartley 2: NASA / JPL / UMD. Churyumov-Gerasimenko: ESA / Rosetta / MPS for OSIRIS Team MPS / UPD / LAM / IAA / SSO / INTA / UPM / DASP / IDA. Wild 2: NASA / JPL. Montage by Emily Lakdawalla.
Scale comparison of comets visited by spacecraft as of August 29, 2014
As of 2014, six comets have been visited by spacecraft; the most recent addition is Rosetta's 67P/Churyumov-Gerasimenko. This version of the montage has now been supplanted by a more recent one.
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!