Today’s photo, taken Monday at a distance of only 145 miles (234 km), gives us a fresh perspective on comet 67P/Churyumov-Gerasimenko. From this angle, the larger lobe faces us, partially hiding the smaller lobe that’s been sticking up like a thumb in recent images. Beside craters, there are about a dozen small ‘dots’ with shadows that may be boulders and interesting variations in tones and textures in and around the smooth regions.
Rosetta is still slowly approaching the comet. Tomorrow, after additional rocket firings to slow it further, the spacecraft will be traveling in tandem with 67P C-G at the same 34,000 mph speed and enter orbit. The final thruster burn will slow the probe relative to the comet to just 3 feet per second – about the same as human walking speed. We’ll also start receiving full-frame pictures of 67P/C-G instead of cropped wide-field views. Can’t wait!
Comet 67P/C-G got its mouthful of a name back in 1969 when astronomers Klim Churyumov and Svetland Gerasimenko of Kiev (now part of Ukraine) discovered it on a photographic plate. The letter ‘P’ refers to ‘periodic’ comets or those that cycle around the sun with periods of fewer than 200 years. The number ’67’ tells us that the comet was the 67th periodic comet to have its orbit determined; the first was famed 1P/Halley.
I’ve seen the 67P on three returns – 1982, 1995 and 2002 – and can honestly say that watching it change in size, brightness and appearance inspired a lifelong interest in comets. “Chury”, as I once called it, led to chasing one fascinating fuzzball after another. Some people make life lists of birds. I keep just one list – comets – and it’s waiting for entry #304.
For more about the Rosetta mission, check out this excellent FAQ.