Although the origins of Venus and Earth share some similarities, their atmospheres evolved in a markedly different way. The composition of Venus' atmosphere - mainly carbon dioxide and nitrogen - results from a running greenhouse effect in the past. The UV radiation from the sun dissociates the carbon dioxide, but to date, the thus released atomic oxygen has not been evidenced yet. Employing the far-infrared spectrometer upGreat, developed and built at the Max Planck Institute for Radio Astronomy (MPIfR) and the Institute of Physics at the University of Cologne in cooperation with the DLR Institute for Optical Sensor Systems, Heinz-Wilhelm Hübers from the DLR institute and his collaborators succeeded in directly detecting the element. As the data analysis suggests, the oxygen is transported from the dayside to the nightside of Venus. The work, which is published today in the journal Nature Communications, is coauthored by three collaborators from MPIfR.