Rosetta Finds Molecular Oxygen on Comet 67P Churyumov-Gerasimenko

Summary: Comet-chasing Rosetta finds molecular oxygen in Comet 67P Churyumov-Gerasimenko's gas cloud, according to a study published in Nature Oct. 29, 2015.

Rosetta's detection of molecular oxygen: spacecraft (ESA/ATG medialab), comet (ESA/Rosetta/NavCam), data (A. Bieler et al., 2015), CC BY SA IGO 3.0, via NASA Scientific Visualization Studio

A study published Oct. 29, 2015, in Nature’s online issue announces the presence of molecular oxygen in the gas cloud surrounding comet 67P Churyumov-Gerasimenko.

Andre Bieler, University of Michigan Department of Climate and Space Science and Engineering physicist at Ann Arbor, and 32 co-authors base their findings on measurements made between September 2014 and March 2015 with ROSINA’s Double Focusing Mass Spectrometer on-board the Rosetta spacecraft.

Analysis of 3,193 mass spectra challenges current solar system formation models of the compound’s difficult, rare detection outside Earth, Jupiter’s moons (Callisto, Europa, Ganymede), Orion Nebula’s and Rho Ophiuchi’s star-forming clouds, and Saturn’s rings. Mainstream theories do not predict cometary molecular oxygen surviving the solar system’s formation 4.6 billion years ago.

Water, carbon monoxide, carbon dioxide and molecular oxygen emerge as the most abundant cometary elements. Kathrin Altwegg, University of Bern Center for Space and Habitability professor in Switzerland and study co-author, finds that “It is the most surprising discovery we have made so far at 67P because oxygen was not among the molecules suspected in a cometary coma.” Constant measurements despite variable solar winds, spacecraft position and ultraviolet radiation furnish evidence contrary to prevailing perceptions of molecular oxygen as quick to bond with hydrogen and resistant to embed within comets.

Michael A’Hearn, University of Maryland distinguished professor emeritus at College Park and Research Professor unaffiliated with the study, indicates that “How the oxygen got there is unclear.”

Sarah Hörst, Johns Hopkins University assistant professor at Baltimore and planetary scientist unaffiliated with the study, judges that molecular oxygen on Calliope, Europa and Ganymede recombines atoms after water splits into hydrogen and oxygen. Dr. Hörst keeps away from explanations that upend current solar system formation models since “There needs to be more work that needs to be done to show that it [the oxygen] isn’t just coming from chemistry in the comet.”

Photolysis and radiolysis lower or modify molecular oxygen and water ratios since ultraviolet radiation breaks bonds and solar wind ionizes molecules. The 33 co-researchers mention 67P’s out-gassing several meters of regolith (surface dust) without Rosetta’s Orbiter Spectrometer for Ion and Neural Analysis detecting decreases.

The study’s 33 co-authors note: “Given that radiolysis and photolysis, on any of the discussed timescales, do not seem to be plausible production mechanisms, the preferred explanation of our observations is the incorporation of primordial O2 into the cometary nucleus.“

The discovery offers possibilities for the detection of molecular oxygen on other comets as well as within interstellar clouds with comet-like temperatures of 20 to 30 degrees Kelvin (minus 423.67 degrees Fahrenheit to minus 405.67 degrees Fahrenheit/minus 253.15 degrees Celsius to minus 243.15 degrees Celsius). It prompts Dr. Altwegg to venture from cometary and solar system formation models and theories to the search for extraterrestrial intelligence: “On this comet we have both [O2 and methane], but we don’t have life. So having oxygen may not be a very good bio-signature [for exo-planets].”

mosaic of four images of comet 67P taken by Rosetta's navigation camera (NAVCAM), Sept. 19, 2014, at distance of 28.6 kilometers (17.8 miles) from comet's center: ESA/Rosetta//NAVCAM, CC BY SA IGO 3.0, via Wikimedia Commons

Acknowledgment

My special thanks to talented artists and photographers/concerned organizations who make their fine images available on the internet.

Image credits:

Rosetta's detection of molecular oxygen: spacecraft (ESA/ATG medialab), comet (ESA/Rosetta/NavCam), data (A. Bieler et al., 2015), CC BY SA IGO 3.0, via NASA Scientific Visualization Studio @ https://svs.gsfc.nasa.gov/30765

mosaic of four images of comet 67P taken by Rosetta's navigation camera (NAVCAM), Sept. 19, 2014, at distance of 28.6 kilometers (17.8 miles) from comet's center: ESA/Rosetta//NAVCAM, CC BY SA IGO 3.0, via Wikimedia Commons @ https://commons.wikimedia.org/wiki/File:Comet_67P_on_19_September_2014_NavCam_mosaic.jpg

For further information:

AFP. 28 October 2015. "Rosetta Finds Molecular Oxygen on Comet 67P (Update)." Phys.org > Astronomy & Space > Space Exploration.
Available @ http://phys.org/news/2015-10-rosetta-molecular-oxygen-comet-67p.html

Bauer, Markus, Kathrin Altwegg, Andre Bieler, Ewine van Dishoeck and Matt Taylor. 28 October 2015. "First detection of molecular oxygen at a comet." Rosetta / NASA Jet Propulsion Laboratory.
Available @ http://rosetta.jpl.nasa.gov/news/first-detection-molecular-oxygen-comet-0

Bieler, A., et al. 29 October 2015. "Abundant Molecular Oxygen in the Coma of Comet 67P/Churyumov-Gerasimenko." Nature 526 (Oct. 29, 2015): 678-681. DOI: 10.1038/nature15707
Available @ http://www.nature.com/nature/journal/v526/n7575/full/nature15707.html

Cesare, Chris. 28 October 2015. "Rosetta Sniffs Oxygen around Comet 67P." Nature > News.
Available @ http://www.nature.com/news/rosetta-sniffs-oxygen-around-comet-67p-1.18658

Kramer, Miriam. 28 October 2015. "In a First, Scientists Detect Oxygen within Atmosphere of a Comet Hurtling through Space." Mashable.
Available @ http://mashable.com/2015/10/28/oxygen-found-in-comet-rosetta/#qOSaj_erFaqI

Pinkowski, Jen. 28 October 2015. "Scientists Discover Oxygen in a Comet." Mental Floss.
Available @ http://mentalfloss.com/article/70415/scientists-discover-oxygen-comet

Ranosa, Ted. 29 October 2015. "Rosetta Scientists Find Oxygen On Comet 67P: How This Gas Came To Be Formed On The Space Rock." Tech Times.
Available @ http://www.techtimes.com/articles/100907/20151029/rosetta-scientists-find-oxygen-on-comet-67p-how-this-gas-came-to-be-formed-on-the-space-rock.htm

"Rosetta Images of Comet 67P on April 5, 2016." NASA Scientific Visualization Studio.
Available @ https://svs.gsfc.nasa.gov/30765

RT. 29 October 2015. "'Big Surprise': Rosetta Finds Primordial Oxygen on 67P Comet." RT > News.
Available @ https://www.rt.com/news/320007-rosetta-comet-oxygen-surprise/

Scalise, Joseph. 29 October 2015. "Stunning: Molecular Oxygen Discovered on Comet 67P." Science Recorder > News.
Available @ http://www.sciencerecorder.com/news/2015/10/29/stunning-molecular-oxygen-discovered-comet-67p/