Amazing New Photo of Rosetta Comet   
       
   This news release is reprinted courtesy of the European Space Agency, which is   
   leading the Rosetta mission to Comet 67P.   
       
   August 2, 2014: As the ESA's Rosetta spacecraft closes to within 1000 km of   
   Comet 67P/Churyumov-Gerasimenko, the Rosetta science team has released a new   
   image and made the first temperature measurements of the comet's core.  The   
   temperature data show that 67P is too hot to be covered in ice and must   
   instead have a dark, dusty crust.   
       
   The new image was acquired on August 1st at 02:48 UTC by the OSIRIS Narrow   
   Angle Camera onboard Rosetta at a distance of approximately 1000 km. It shows   
   the rough surface of the double-lobed core in amazing detail.   
       
   http://blogs.esa.int/rosetta/2014/08/02/comet-at-1000-km/   
       
   OSIRIS narrow angle camera view of 67P/C-G from a distance of 1000 km on 1   
   August 2014. Note that the dark spot is an artefact from the onboard CCD.   
   Credits: ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA   
   Full image and caption   
       
   Thermal observations of comet 67P/Churyumov-Gerasimenko were made by Rosetta's   
   visible, infrared and thermal imaging spectrometer, VIRTIS, between 13 and 21   
   July, when Rosetta closed in from 14 000 km to the comet to just over 5000 km.   
       
   At these distances, the comet covered only a few pixels in the field of view   
   and so it was not possible to determine the temperatures of individual   
   features. But, using the sensor to collect infrared light emitted by the whole   
   comet, scientists determined that its average surface temperature is about   
   -70øC.   
       
   Although -70øC may seem rather cold, importantly, it is some 20-30øC warmer   
   than predicted for a comet at that distance covered exclusively in ice.   
       
   "This result gives us the first clues on the composition and physical   
   properties of the comet's surface," says VIRTIS principal investigator   
   Fabrizio Capaccioni from INAF-IAPS, Rome, Italy.   
       
   Other comets such as 1P/Halley are known to have very dark surfaces owing to a   
   covering of dust, and Rosetta's comet was already known to have a low   
   reflectance from ground-based observations, excluding an entirely 'clean' icy   
   surface. The temperature measurements provide direct confirmation that much of   
   67P's surface must be dusty, because darker material heats up and emits heat   
   more readily than ice when it is exposed to sunlight.   
       
   https://www.youtube.com/watch?v=KQL_43SFHzw&feature=youtu.be   
       
   The ESA has prepared a must-see visualization of what sunrise over the comet   
   might look like. Play it   
       
   "This doesn't exclude the presence of patches of relatively clean ice,   
   however, and very soon, VIRTIS will be able to start generating maps showing   
   the temperature of individual features," adds Dr Capaccioni.   
       
   As Rosetta approachs and later orbits the comet, the sensor will study the   
   variation of daily surface temperatures in order to understand how quickly the   
   surface reacts to solar illumination. In turn, this will provide insight into   
   the thermal conductivity, density and porosity of the top tens of centimetres   
   of the surface--important data to help select a target site for Rosetta's   
   lander, Philae.   
       
   It will also measure the changes in temperature as the comet flies closer to   
   the Sun along its orbit, providing substantially more heating of the surface.   
       
   "Combined with observations from the other 10 science experiments on Rosetta   
   and those on the lander, VIRTIS will provide a thorough description of the   
   surface physical properties and the gases in the comet's coma, watching as   
   conditions change on a daily basis and as the comet loops around the Sun over   
   the course of the next year," says Matt Taylor, ESA's Rosetta project   
   scientist.   
       
   "With only a few days until we arrive at just 100 km distance from the comet,   
   we are excited to start analysing this fascinating little world in more and   
   more detail."   
       
   Credits:   
   Production editor: Dr. Tony Phillips | Credit: Science@NASA   
       
   Rosetta is an ESA mission with contributions from its member states and NASA.   
   Rosetta's Philae lander is provided by a consortium led by DLR, MPS, CNES and   
   ASI. Rosetta will be the first mission in history to rendezvous with a comet,   
   escort it as it orbits the Sun, and deploy a lander.   
       
   Web links:   
   European Space Agency home page   
       
   Rosetta -- from the ESA   
       
   Rosetta -- from NASA   
       
   NASA Instruments on Rosetta   
       
   Rosetta Comet Comes Alive -- from Science@NASA   
       
       
   Regards,   
       
   Roger   
      
   --- D'Bridge 3.99   
    * Origin: NCS BBS - Houma, LoUiSiAna (1:3828/7)