Capturing the Comet’s Jets—Rosetta Mission Gets Up Close and Personal

This summer has been one of many great successes for the European Space Agency's (ESA) Rosetta spacecraft. Finally arriving to its intended destination, Comet 67P/Churyumov-Gerasimenko, and entering its orbit successfully, Rosetta has begun its year-long work of observing and analyzing the comet with quite a splash. And now, only weeks into observation, at only a distance of 16 miles away from the comet, the spacecraft's camera has captured a glimpse of jetting vapors released from the icy surface.

Found at the comet's "neck" connecting its two-lobed halves, the jet of vapor is a phenomenon caused by the orbit around the sun. As the comet comes closer to the sun in parts of orbit, solar heating triggers sublimation of frozen water and volatiles trapped beneath the surface, blasting high-speed gases laced with dust out into space. While sublimation, which is rarely seen on Earth with the exception of dry ice, is fairly common on comets much like Comet 67P/Churyumov-Gerasimenko, witnessing this emission of gases gives astronomers and Rosetta a glimpse at the universe's past.

As primordial masses composed of the substances frozen at the dawn of our solar system, comets act as the record keepers of space. And the vapor unlocked in this jet reveals a little bit about the chemical compositions of the cosmos when our star arose billions of years ago.

And while the dynamic behavior of the comet allows for Rosetta to get a glimpse from up close and personal, the ESA can expect to find a lot more out about our solar system's origins and major cosmic events early this November when they enter the next phase of the mission. As a proper landing site has already been selected, Rosetta's Philae lander is scheduled to launch on November 12, to collect samples and run diagnostics from the surface of the comet. And researchers are expecting exciting findings when the Philae arrives.

"There is no doubt that the [Philae Lander] will have highest priority and importance, and it may be the phase that receives a lot of attention by the scientific community and the public" researchers at the Max Planck Institute for Solar System Research say. "Since it will last only 2-3 days, it will provide a kind of spotlight view of the comet and what is going on at the surface and underneath. It will provide 'a first taste of the comet' in a way impossible to achieve through orbiting spacecrafts."