Are You Ready For Perihelion?

After a year on station at comet 67P/CG, Rosetta will fly along past perihelion on August 13. Over the past few months, Rosetta has observed the changes as the comet heats up, spewing gas and dust. This process will reach a climax in the next month or two, as the comet swoops by and heads out away from the sun again.

ESA has a nice FAQ on this especially interesting part of the mission.

67P/CG doesn’t come very near the Sun (at the closest, not as close as Earth’s orbit), so it isn’t likely to fall apart or explode or anything really exciting. But there will certainly be changes as the surface heats and boils away. Rosetta will be the first close up of this process ever, so who knows what we might see and learn?

For perspective, I note the sort of data we have had before this, from telescope observations, such as:

Recent image from the 2 m Liverpool Telescope, taken on the morning of 19 July 2015. It comprises 10 x 20s r-band images. The length of the tail visible in the image in the twilight sky is approximately 120,000 km. Credit: Colin Snodgrass / Geraint Jones / Liverpool Telecope

For comparison, recent images alone are zillions of times more detailed:

Comet 67P/C-G on 20 July 2015. Credits: ESA/Rosetta/NAVCAM – CC BY-SA IGO 3.0

The instruments are generating a lot of detailed science, with many results just being published now. (No, I have not read these reports!)


  1.  Bibring, J. P., M. G. G. T. Taylor, C. Alexander, U. Auster, J. Biele, A. Ercoli Finzi, F. Goesmann, G. Klingelhoefer, W. Kofman, S. Mottola, K. J. Seidensticker, T. Spohn, and I. Wright, Philae’s First Days on the Comet. Science, 349 (6247):493-493,  2015.


Space Saturday


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