Scientists were baffled when Europe’s Rosetta mission detected molecular oxygen coming from a comet called 67P in 2015. Molecular oxygen is made up of two oxygen atoms (O2) and is what we happen to breathe here on Earth. However, when introduced to space, it becomes highly unstable so seeing it come from a comet didn’t make sense. It also happens to be a highly reactive compound that attaches itself to other chemicals like carbon (creating CO2) and hydrogen (creating H20).

Ancient comets

Comets were created around 4.6 billion years ago, out of the same mess that built our own solar system. The Rosetta spacecraft’s mission was to understand the composition of the comet so we could better understand what the solar system may have looked like in the beginning.

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Astronomers believe that O2 erupting from the comet means that oxygen has been locked in the comet’s ice for 4.6 billion years. It is only released as the sunlight heats the comet’s surface producing water particles. However, not everybody believes this theory. One chemical engineer believes that he may have found the true answer in his lab.

Oxygen is produced not stored

Konstantinos P. Giapis believes that the comet produces oxygen on its own. His primary research involves chemical reactions between energetic ions colliding with semiconductor surfaces in order to create better computer microchips.


In his lab, Giapis was able to show that as these water particles hit the comet’s surface, they attach to oxygen atoms contained in other molecules like rust (iron oxide). New chemical bonds are created after the collision and molecular oxygen is then produced and vented into space.

It’s not all good news

This may seem like good news but it actually poses a problem for another area of astronomy. Astronomers who are currently looking for extraterrestrial life somewhere else in the galaxy hope to use powerful telescopes and high-resolution spectrometers to probe the atmospheres of exoplanets light-years away.

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In other words, they’ll look for biomarkers that are known to be associated with life. Now that astronomers know that O2 can be produced outside of a biological process, it creates an uncertain result in the search for these chemicals. Hopefully, we will be able to get around this issue with better technology.