Stereo Pair of Comet 67P
October 02, 2015
Summary Author: Brian May
Credits: ESA/ROSETTA/NAVCAM; Matt Taylor; Bernhard Geiger; Greg Parker
Stereo by Brian May
Shown above is a stereo pair of an unusual view of Comet 67P as observed by the Rosetta probe -- Rosetta’s wider-angle navigation camera. This pair of images was kindly given to me by Matt Taylor and Bernhard Geiger of the European Space Agency's Rosetta mission. From this angle, as the Rosetta probe passes along a trajectory some 208 mi (332 km) from the comet, we see 67P from the top down. It looks like a burning cinder in the sky. Of course, it’s not burning, but since it was close to its perihelion (August 13, 2015) it was about as warm as it'll get in this orbit, around 85 F (30 C). The image was actually acquired on August 8, 2015.
We’re looking at a side-on view of the sunlit part of 67P, which also allows us a view of the dark side of the comet. The unlit portion of the comet’s surface is very dark, and we wouldn’t see it at all except for the fact that it’s silhouetted against part of the dusty coma. With the magic of 3-D, however, now that these two images are suitably aligned, we can clearly make out the C67P's three-dimensional shape -- its two lobes, one behind the other, in our line of sight. There’s also evidence here for the ever-changing pattern in the eruptions from its surface as it warms up. Left of center we can see a jet in the left image flashing in our three-dimensional view, indicating that a jet was present when the left-hand image was captured, but not in the right image.
This image pair can be viewed by free viewing and by using a stereo viewer such as the OWL. Click here for instructions on how to view using both of these approaches.
Photo Details: Times logged for the two component images are: August 12, 2015, 09:05:03 and August 12, 2015, 09:24:52. Thus, there's about a 20 minute time difference between these two exposures. At its speed in the comet’s frame of reference, approximately 2 mi per hour (3 km per hour), about 2/3 mi (1 km) has been covered. This is then the baseline of this stereo pair.