Getting closer ...
This shot was taken by the Rosetta spacecraft on Aug. 1, 2014, when it was just over 1,000 kilometers (630 miles) from the comet 67P/Churyumov-Gerasimenko. It has twice the resolution as the picture I posted a few days ago (I enlarged the image a bit), and we're about a week away from Rosetta entering orbit, 100 kilometers from the dirty ice ball—photos taken at that point will have 10 times the resolution of this one.
It looks very much like we're starting to see rubble on the surface—the white spot to the upper right is casting a shadow, and it looks to be about 100 meters across or so. Update, Aug. 2, 2014 at 18:15 UTC: The "rubble" in the above NAVCAM image doesn't appear to be in the OSIRIS image below, so they look like they're image artifacts (sometimes you get oddities in images that aren't real due to cosmic rays and other events). I shouldn't have jumped to a conclusion... as I say in the first update below, I'll hold off speculating further ...
I can't wait for the higher-res shots!
Update, Aug. 2, 2014 at 18:00 UTC: And no sooner do I post this that I find out that a higher-res OSIRIS camera image has been released! It's amazing.
We're seeing lots of detail here, though it's difficult to say just yet what exactly is going on. The surface is definitely rough, though it has smoother areas, much like those seen in previously visited comets. I won't speculate here, since we'll know better very very soon. Read Emily Lakdawalla's post at The Planetary Society for more.
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