During the day, oxygen is produced in the atmosphere of Venus. It would be rather difficult to breathe in it

Oxygen makes up about 21 percent of Earth’s atmospheric air and is essential for most living organisms. It is more difficult to find it on neighboring Venus, whose dense atmosphere is dominated by carbon dioxide – it is as much as 96.5 percent. As a study published in Nature Communications shows, this does not mean that the planet’s atmosphere is completely devoid of this element.

To study Venus, scientists used the upGREAT spectrometer mounted on board the SOFIA observatory – a modified Boeing 747SP aircraft built by NASA and the German Space Agency (DLR). Researchers looked at the planet’s atmosphere several times at 17 points, both on the side facing the Sun and on the side where it was night.

Observations confirmed that there was atomic oxygen in the atmosphere. Most of the element was observed at an altitude of about 100 kilometers above the surface of Venus, between two parts of the atmosphere where the wind blows in opposite directions. The temperature of the atoms ranged from about -120 degrees Celsius during the day to -160 degrees C at night.

Researchers detected oxygen on the day side of the planet for the first time and also confirmed its presence on the night side – it had previously been observed by an observatory in Hawaii. Interestingly, this is not the same oxygen that we breathe on Earth: unlike the well-known molecular oxygen (O₂) these are just single atoms.

As the study authors explained, atomic oxygen is produced on the dayside of the planet by ultraviolet radiation from the Sun, which decomposes atmospheric carbon oxides. Some of the oxygen is then transported by wind to the night side of Venus.

– The detection of atomic oxygen on Venus is direct evidence of the existence of photochemical processes driven by UV radiation, said Helmut Wiesemeyer from the Institute of Radio Astronomy. Max Planck, co-author of the study. – On Earth, an example of such photochemistry is the stratospheric ozone layer that protects our lives.

Studying Venus’ atmosphere could help scientists understand why it is so different from Earth. Although similar in size, it is not a place friendly to life – the average temperature on its surface is about 464 degrees Celsius, and there are gales in the atmosphere reaching speeds of about 700 kilometers per hour.

“We are still at the beginning of understanding the evolution of Venus and why it is so different from Earth,” said Heinz-Wilhelm Hübers of DLR, lead author of the study.