The " dark side " of Comet 67P Churyumov - Gerasimenko has come into sentiment of the Rosetta spacecraft for the first time . Specifically , it has examine a part near the comet ’s south perch that experiences a long and cold wintertime , which had antecedently been in darkness for five years .
Comet 67P involve 12.4 hour to rotate , while it takes 6.5 years to orbit the Sun , but not all of the comet receives equal amounts of sunlight owe to its irregular shape . The northerly hemisphere experiences a summertime last 5.5 years , while the southern hemisphere has only a poor and brief summertime when the comet is closest to the Sun , which will last until early 2016 .
In August this year , the comet reached itsclosest pointto the Sun – known as its perihelion – and Rosetta was there for the ride . This stand for the spacecraft was able to learn the southern cerebral hemisphere using all its official document . Only the Microwave Instrument for Rosetta Orbiter ( MIRO ) instrument had investigate it before , with initial solvent from those reflexion published in the journalAstronomy and Astrophysics .
The effect intimate it has an intriguing and different composition compared to the rest of the comet , and now that it has been illuminate by sun , Rosetta will be capable to canvas it in even bang-up detail using the sleep of its instruments .
" We observed the ' dark side ' of the comet with MIRO on many occasions after Rosetta ’s arriver at 67P / C - G , and these unique data are telling us something very intriguing about the material just below its surface , " enounce Mathieu Choukroun from NASA ’s Jet Propulsion Laboratory ( JPL ) , Pasadena , California , Pb author of the study , in astatement .
For example , the squad thinks there might be large sum of money of ice in the first few ten of centimeters beneath the surface in this region , being mostly composed of water ice or carbon paper dioxide ice . " Surprisingly , the thermal and electric holding around the comet ’s south pole are quite different than what is recover elsewhere on the nucleus , " said Choukroun .
The accurate unconscious process at maneuver in this part are n’t fully known , though . One possible action is that water and gasoline released during the previous perihelion distil on the aerofoil , stay in place until this subsequent " summer . " Data take during this seasonal change should shed more visible radiation on the processes taking place .
Rosetta is now being placed in a remote orbit about 1,500 klick ( 930 miles ) from the comet , to honour its palisade coma ( atmosphere ) as a whole , before afterwards being brought into secretive orbits to study its surface in more item .
persona in textbook : A view of the south polar realm taken on 31 December 2024 . ESA / Rosetta / NAVCAM – CC BY - SA IGO 3.0 .
