ozone
Surprising discovery of molecular oxygen on comet 67P
ESA’s Rosetta spacecraft has made the first in situ detection of oxygen molecules outgassing from Comet 67P/Churyumov-Gerasimenko, a surprising observation that suggests they were incorporated into the comet during its formation. This may have implications for our understanding of the chemistry involved in the formation of the solar system some 4.6 billion years ago.