For the first time ever, scientists have detected oxygen on a comet, a discovery that could challenge theories about the solar system’s formation.

The international team of researchers published their findings in Wednesday, stating that an unexpectedly large amount of molecular oxygen was found in the cloud of gas, or coma, surrounding comet 67P/Churyumov-Gerasimenko’s nucleus.

The discovery was made by the , an instrument aboard the Rosetta spacecraft, which has been tailing the comet since August 2014, reports the Los Angeles Times. While common on Earth, molecular oxygen is rarely seen anywhere else, making this find all the more important.

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“It is the most surprising discovery we have made so far in 67P, because oxygen was not among the molecules suspected in a cometary coma,” said Kathrin Altwegg of the University of Bern and co-author of the study, during a press conference. “The first time we saw it I think we all went a little bit into denial because it was not expected to be found in a comet.”

Previously, oxygen’s presence was ruled out on comets because it blends easily with other elements, and scientists “never thought that oxygen could ‘survive’ for billions of years" in a pristine state, said Altwegg.

However, the ROSINA instrument found that in 67P’s gaseous coma, after water, carbon monoxide and carbon dioxide.

This photo shows Comet 67P/Churyumov-Gerasimenko by Rosetta's OSIRIS narrow-angle camera on Aug. 3, 2014, from a distance of 285 km.

(ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA)

“Our study merely suggests that our current models [of the solar system] most probably are not right,” André Bieler of the University of Michigan told FoxNews.com.

After studying 67P for several months, the researchers concluded that , reports FoxNews.com. This raised the question of how the oxygen managed to form and remain present for billions of years.

, a process in which energetic particles radiating from the sun break up the bonds of water ice. Hydrogen can diffuse out, leaving oxygen behind with no other molecules to react with. However, this is an unlikely explanation for the oxygen in 67P.

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The next probable option is that the . Pristine, icy grains containing oxygen , reports Phys.org.

“This work tells us that the building process of our solar system had to be very gentle for those ice grains to never have really been heated up or reprocessed,” said Bieler.

Despite the major implications of this find, scientists say , as more time is need to assess the implications.

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