An international team of astronomers has made the first detection of oxygen molecules in space. Until now no searches had turned up oxygen in its molecular form - two atoms of oxygen bonded together, but the team from Herschel Oxygen Project believes that this study would explain where some of the oxygen might be hiding.

Using data from the European Space Agency's (ESA) Herschel space observatory, the largest astronomical telescope ever launched, the Herschel Oxygen Project team was able to see molecules of oxygen in the nearby Orion star-forming complex.

In trying to explain the lower-than-expected oxygen level, astronomers suggested that oxygen atoms may freeze onto tiny dust grains found floating in space and be converted to water ice, which effectively removes them from sight. With their hypotheses, the ice should evaporate in warmer regions of the cosmos, returning water to the gas and allowing molecular oxygen to form and to be seen.

In order to get the data, the team used Herschel's Heterodyne Instrument for the Far Infrared (HIFI) and targeted Orion, where they reasoned that the forming stars would heat the surrounding gas and dust. In conclusion, they found there to be one molecule of oxygen for every million hydrogen molecules.

According the astronomers, this study explains where some of the oxygen might be hiding. For that reason, whilst this study has made groundbreaking steps in the search for oxygen, but the search continues.