Dramatic changes seen in comet 67P/Churyumov-Gerasimenko close to perihelion

Posted in Comet 67P, Rosetta

Two recent scientific publications indicate the dynamic nature of comets as they pass near the Sun. An analysis of images taken from the Rosetta spacecraft show that a large crack between the two halves of the comet has grown, thought to be because the spin of the comet was altered as large amounts of gas and dust (to depths of several meters per day) were ejected in jets heated by the Sun. Furthermore, a different team of authors has shown that a 100 m high cliff on the comet collapsed (in July 2015, shortly before the comet came closest to the Sun in August 2015). Amazingly, the OSIRIS camera onboard Rosetta actually captured the debris plume of about one thousand tonnes of material associated with this collapse. The supplementary figures to this paper include anaglyphs of the cliff region – 3D images that can be viewed through red and cyan filters, and a video illustrating the event.

Although this work was not done as part of the MiARD project, many of the authors of the two studies linked to above are also contributing to the project work, and a major goal of the detailed shape models being produced by the MiARD project team is to enable the study of the geomorphology of the comet, including changes over time.

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Spring equinox and the Earth’s motion

Posted in Uncategorised

Although this has nothing to do with comets, since the tradition in many northern hemisphere countries is that Spring starts with the vernal equinox, here is a video on YouTube that explains the surprisingly complicated orbital motion of the Earth. The video was originally from the Cassiopeia project, which produces videos to explain scientific concepts.

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