Comet Hartley2 - provisional diagnosis

18 Jun 2011

NASA has released preliminary information on its Deep Impact mission of November 2010 when a spacecraft flew near Comet Hartley2. It is a small cosmic body with a six and a half year orbit around the Sun and appears to eject huge amounts of dust and gas. Most of this activity, they say, is confined to one part of the comet - which they describe as a large halo of fluffy, icy grains. Chandra detected x-ray emissions - due to the impact of atoms in the solar wind with molecular gas surrounding the comet. Modelling has already begun and this has been used to claim carbon dioxide gas evaporates from the comet and is the dominant driver of its activity - but this is a model so that is not a given. See also www.physorg.com/print227348078.html for the same story. At www.physorg.com/print227450522.html  we learn that a paper has been published in Science June 16th on the same subject, 'NASA Epoxi flyby of hyper comet' which the NASA press release pre-emptied. Comet Hartley2 spins around one axis but also tumbles around a different axis and at its two ends the surface is clotted with glittering blocks 50m high and 80m wide. They appear to be more reflective than the main body of the comet.

Meanwhile, NASAs Dawn spacecraft is approaching the Vesta asteroid - and a small video can be watched at www.nasa.gov/dawn and www.sciencedaily.com/releases/2011/06/110613135604.htm with images etc