California Institute of Technology | 2017 May 08
[img3="Konstantinos Giapis has shown how molecular oxygen may be produced on the surface of comets using lab experiments. He and his postdoctoral scholar Yunxi Yao fired high-speed water molecules (left) at oxidized silicon and iron surfaces, observing the production of a plume that included molecular oxygen. Oxygen atoms are red, and hydrogen, blue. (Credit: Caltech)"]http://s3-us-west-1.amazonaws.com/www-p ... WS-WEB.jpg[/img3][hr][/hr]A Caltech chemical engineer who normally develops new ways to fabricate microprocessors in computers has figured out how to explain a nagging mystery in space—why comets expel oxygen gas, the same gas we humans breathe.
The discovery that comets produce oxygen gas—also referred to as molecular oxygen or O2—was announced in 2015 by researchers studying the comet 67P/Churyumov–Gerasimenko with the European Space Agency's Rosetta spacecraft. The mission unexpectedly found abundant levels of molecular oxygen in the comet's atmosphere. Molecular oxygen in space is highly unstable, as oxygen prefers to pair up with hydrogen to make water, or carbon to make carbon dioxide. Indeed, O2 has only been detected twice before in space in star-forming nebulas.
Scientists have proposed that the molecular oxygen on comet 67P/Churyumov–Gerasimenko might have thawed from its surface after having been frozen inside the comet since the dawn of the solar system 4.6 billion years ago. But questions persist because some scientists say the oxygen should have reacted with other chemicals over all that time. ...
Dynamic Molecular Oxygen Production in Cometary Comae - Yunxi Yao & Konstantinos P. Giapis
- Nature Communications 15298 (08 May 2017) DOI: 10.1038/ncomms15298
