In case you couldn’t tell, I’m kind of excited about the Rosetta mission to Comet 67P/Churyumov-Gerasimenko. Today, the European Space Agency published a fresh, more detailed photo taken on July 31. Notice how rugged the comet’s surface looks. Right away I thought of another comet with a similar appearance, 81P/Wild.
NASA flew the Stardust spacecraft past the comet in January 2004, took photos and measurements and collected particles from 81P’s coma that were later returned to Earth for study. If you compare the photos, both show lots of shallow depressions.
It’s speculation only, but there appear to be two small hills, large boulders or even spires near the top of 67P’s smaller lobe. Studying the photo closely, the direction of sunlight is from the bottom up . Whatever the two bright dots are, they rise above the general landscape because they cast clear shadows. The lower rims of several of the comet’s ‘craters’ are rimmed with shadow as well.
Just a caution – I could be wrong about this interpretation. The little hills or whatever they are may be little more than image artifacts.
Either way, looking at the photo makes me feel like I need a new glasses prescription. So much detail is tantalizingly close to coming into clear focus. We’re not quite there yet.