Fresh images from Rosetta reveals surface detail of comet quarry
By Anthony Wood
July 28, 2014
The ESA's Rosetta spacecraft is now close enough to its target, the comet 67P/Churyumov-Gerasimenko (67P), to begin to discern some of the surface features marking the face of the lonely wanderer. Taken from a distance of 3,400 miles (5,500 km), the images will provide the first detailed insight into the comet due to be visited by Rosetta's Philae lander in November 2014.
Few unmanned NASA missions have managed to garner as much tension and excitement as the Rosetta spacecraft. The probe has been the focus of intense media curiosity, from the suspense-filled interlude as the world waited for her to wake, continuing through the probe's gradual approach to her target, 67P.
Rosetta has now drawn close enough to 67P to resolve some of the features marking the face of the comet. The images were snapped using the spacecraft's OSIRIS system, providing detailed shots with a resolution of 100 m per pixel. Earlier images revealed that the comet consisted of two huge boulder-like structures, the head and the body, connected by a thinner neck section.
The most recent set of images seem to reveal an interesting characteristic, with the neck apparently displaying a lighter-colored surface compared to the head and body of 67P. It is currently theorized that this peculiarity could be the result of the neck being comprised of a different material than that which constitutes the rest of the comet. In order to determine the validity of this theory, NASA scientists will perform spectral analysis over the coming weeks, analyzing the light reflected by the comet in an attempt to determine the material composition of the neck.
Conversely it is possible that the lighter color could simply be the result of a smaller size particle layering the surface of the comet's neck. Another explanation for the high level of reflectivity could involve the surface structure of the neck compared to the sections either side. The more detailed images captured of the comet have revealed that the neck's surface is much smoother than the rougher head and body of 67P.
This smoother surface would mean that less light is refracted and scattered away in different directions, as is the case with the uneven surfaces exhibited on either side of the neck, thus creating the brighter areas picked up by the recent observations by the probe. Whatever the reason for the disparity in color, with the images captured at a distance of around 3,400 miles (5,500 km) out from the comet, we may have to wait for Rosetta to close the distance a little before the solution to the riddle presents itself.
Working with the fresh data captured by Rosetta as it closes on 67P, NASA scientists were able to create a 3D model of the comet's nucleus.