This image of the coma of comet 67P/Churyumov-Gerasimenko, seen with ESA'S OSIRIS onboard the Rosetta spacecraft, shows the hazy circular structure to the right and center of the coma is an artifact due to overexposure of the nucleus.
Images of comet 67P/Churyumov-Gerasimenko taken on July 14, 2014, by the OSIRIS imaging system aboard ESA's Rosetta spacecraft have allowed scientists to create this three-dimensional shape model of the nucleus.
This observation from ESA's Rosetta spacecraft shows that comet 67P/Churyumov-Gerasimenko has a two-part shape. The image on the left is from OSIRIS; the image on the right is enhanced with interpolated data.
Comet NEOWISE was first observed by NASA's NEOWISE spacecraft on Valentine's Day, 2014. This heat-sensitive infrared image was made by combining six exposures taken by the NEOWISE mission of the newly discovered comet.
Three of NASA's contributions to the ESA's Rosetta mission are pictured here: an ultraviolet spectrometer called Alice (top), the Ion and Electron Sensor (IES) (bottom left), and the Microwave Instrument for Rosetta Orbiter (MIRO) (bottom right).
New measurements from NASA's Herschel Space Observatory have discovered water with the same chemical signature as our oceans in a comet called Hartley 2 (pictured at right). The image at bottom right is an artist's concept of a comet.