The telescopes, G.R.E.A.T (German Receiver for Astronomy at Terahertz Frequencies) and S.O.F.I.A (Stratospheric Observatory for Infrared Astronomy) took seventeen observations of Venus in November 2021 and measured its atmospheric density, confirming the presence of oxygen. By measuring the temperature of this oxygen, scientists were also able to determine that it existed around 100km above Venus' surface.
Oxygen has been detected before in Venus' atmosphere, but only on the night side - its dark side. However, oxygen has now been confirmed as present on both sides of the planet. Scientists believe this is due to the build-up of oxygen as heat breaks down carbon dioxide and carbon monoxide. This oxygen is transported to the planet's nightside due to convection currents - winds high in the atmosphere - where it gradually reacts with other elements.
Of course, humans would not be able to breathe these small amounts of oxygen. Breathable oxygen consists of two bonded oxygen atoms, whereas the oxygen detected is molecular - single, free-floating oxygen atoms - so it reacts too quickly with lung tissue and cannot reach the bloodstream effectively.
In that case, why is this discovery important? One of the biggest questions facing astrophysicists is the past of planets in our solar system. The fact that Venus has oxygen in its atmosphere hints at a calmer, milder world in the past, which lends information about the formation of planets and our solar system.
One of the theories on this is Venus' runaway greenhouse effect - heat trapping due to insulating gases. As Earth's greenhouse effect becomes stronger, leading to significant climate change, Venus' past may provide insight into our future. Not only this, but Venus is often referred to as Earth's "twin" planet - the two worlds are similarly sized, neighbours, and have similar densities and compositions. Perhaps this new information about Venus will lead us to more details on the formation and evolution of our planet.
Furthermore, there are two upcoming NASA missions to Venus - DAVINCI (2029) and VERITAS (2031), as well as the ESA mission EnVision (2031). The objectives of these missions are to understand Venus' origin and evolution, especially that of its atmosphere. The discovered about Venus, the more mysteries remain. One of the biggest questions is how and why Venus is different to Earth and Mars - and this discovery brings us another step closer to the answer.