Molecular oxygen has been discovered on 67P/Churyumov-Gerasimenko, a comet originally from the Kuiper belt, by European Space Agency's (ESA) Rosetta spacecraft. Researchers said it is the first time when the gas has been detected on a comet.

Andre Beiler from the University of Michigan said the researchers believe that the gas is primordial, which means it is older than the solar system. The researchers published their finding in the journal Nature. Oxygen's presence on the comet could several interesting things about the creation of the solar system, they suggested.

The researchers also said the discovery was surprising as they had never thought that oxygen would be present in comets like 67P/Churyumov-Gerasimenko as it mixes easily with other elements.

Kathrin Altwegg, a researcher at the University of Bern in Switzerland and co-author of the study, said, "We never thought that oxygen could survive for billions of years in a pure state. It is the most surprising discovery we have made so far, because oxygen was not among the molecules expected in a cometary coma".

The gas was discovered by Rosetta spacecraft's instrument, Rosetta Orbiter Spectrometer for Ion and Neutral Analysis. Now, the researchers are hoping the coma, gas cloud surrounding the comet, could also contain carbon dioxide, water and carbon monoxide.

According to Altwegg, the new discovery will possibly challenge some old and current theories about how our solar system was formed. The evidence about oxygen will discredit some current models about the formation of the solar system, she added.