Modern Mystery: Ancient Comet Is Spewing Oxygen
The Rosetta spacecraft has detected molecular oxygen in the gas streaming off comet 67P/Churyumov-Gerasimenko, a curious finding that has scientists rethinking the ingredients that were present in the early solar system.
What's mystifying astronomers about the new find is why the oxygen wasn't annihilated during the solar system's formation. Molecular oxygen is extremely reactive with hydrogen, which was swirling in abundance as the sun and planets were created. Current solar system models suggest the molecular oxygen should have disappeared by the time 67P was created, about 4.6 billion years ago.
"It was a big surprise to actually detect the O2 [oxygen]," Andre Bieler, a research fellow at the University of Michigan who co-led the study, said in a media briefing held by the journal Nature, where the new research was published.
While the study suggests solar system modelling may need revision, Bieler and co-author Kathrin Altwegg, a space scientist at the University of Bern — both of whom are cometary scientists and not modeling experts — said they could not speculate too much on what, exactly, would change about those models.
Meanwhile, the scientists said they are trying to find molecular oxygen in the 1986 Giotto spacecraft observations of Halley's Comet, the only other comet to get a close-up visit from a spacecraft. The spectral lines of oxygen are too faint to be seen from Earth. This means that even though molecular oxygen may be common in other comets, there is no way yet to confirm that theory.