As I commented earlier, we can expect a flood of science results from Rosetta this fall and winter. Unlike Hollywood, we don’t get back instant results, nor is every discovery a photogenic movie. We got back data that must be carefully analyzed and then reported in conferences and articles. That takes time, but we know when the conferences are going to happen so we know when results will appear. (The raw date will be available for everyone as the publications come out.)
Indeed, we have seen the first of these publications in the last few weeks, too many for me to keep up with, including, “How Rosetta’s comet got its shape” (spoiler alert: there was a low speed collision of two icy balls).
Skimming through the blog, I picked one to look at in more detail. One of the more interesting things about visiting a comet is how it changes as it approached (and leaves) perihelion. Several papers will discuss the atmosphere and magnetosphere of 67P/CG, but we also have months worth of images of the surface, which reveal the rapid change as things heated up.
As reported in a letter in Astronomy & Astrophysics , the optical imaging detected the rapid development and growth of surface features (craters? crevasses? Terran terminology probably doesn’t apply). This is one of the first and certainly the most detailed observation of such processes ever achieved.
The changes are consistent with collapsing materials, presumably as underlying ice and other volatile material heats in the sun, melts and boils. The changes appear to expose other materials including what may be ice. They proceed in an organized wave that moves as much as 10 cm per day (which is pretty fast for erosion!)
The investigation is incomplete. No jets of particles was spotted by the optical imagery, which leaves open the question of where the material went. The phenomena were only observed in smooth regions, raising questions about the different processes that might have occurred in the rougher regions.
These studies will incorporate data from the other instruments to fill out the picture and perhaps answer some of the questions.
“The dramatic changes observed on Imhotep are a spectacular event, unique to comets, with a currently unpredictable end state.” Rosetta has given us a unique opportunity to learn something about this “spectacular event”, close up, and in detail.
- Barbieri, P. Lamy, R. Rodrigo, D. Koschn, H. Rickman, H. U. Keller, M. F. A’Hearn, A.-T. Auger, M. A. Barucci, J.-L. Bertaux, I. Bertini, S. Bess, G. Cremonese, V. Da Deppo, B. Davidsson, S. Debei, M. De Cecco, M. R. El-Maarry, S. Fornasier, M. Fulle, P. J. Gutiérrez, C. Güttler, S. Hviid, W.-H Ip, L. Jorda, J. Knollenberg, G. Kovacs, J. R. Kramm, E. Kührt, M. Küppers, L. M. Lara, M. Lazzarin, J. J. Lopez Moreno, S. Lowry, S. Marchi, F. Marzari, M. Massironi, S. Mottola, G. Naletto, N. Oklay, M. Pajola, A. Pommerol, N. Thomas, I. Toth, C. Tubiana, and J.-B. Vincent, Temporal morphological changes in the Imhotep region of comet 67P/Churyumov-Gerasimenko. Astronomy & Astrophysics, (to appear) 2015. http://dx.doi.org/10.1051/0004-6361/201527020