Green emissions from Venus

Astronomers have used a high-resolution spectrograph at the Keck I telescope, in the us, to obtain the spectra of the atmosphere of Venus and reported a strong green line emission. Studying the composition of planetary atmospheres is crucial to understanding their evolution and structure. One way to do it is to study the optical emissions, which result when solar radiation falls on the planetary atmosphere. In particular, atomic oxygen has a characteristic green line emission that can be used to guess the density of oxygen atoms in the atmosphere. (Science , Vol 291, No 5503).