On Earth, the glow of hydroxyl in the atmosphere has been shown to be closely linked to the abundance of ozone. From this study, the same is thought to be true at Venus. Now, scientists can set about estimating the amount of ozone in the planets atmosphere.
Venus Express has shown that the amount of hydroxyl at Venus is highly variable. It can change by 50% from one orbit to the next and this may be caused by differing amounts of ozone in the atmosphere.
Ozone is an important molecule for any atmosphere, because it is a strong absorber of ultraviolet radiation from the Sun, says Piccioni. The amount of the radiation absorbed is a key parameter driving the heating and dynamics of a planets atmosphere. On Earth, it heats the stratosphere (layer of the atmosphere) making it stable and protecting the biosphere from harmful ultraviolet rays.
Computer models will now be able to tell how this jump and drop in ozone levels over short intervals affects the restless atmosphere of that world.
Venus Express has already shown us that Venus is much more Earth-like than once thought. The detection of hydroxyl brings it a step closer, says Piccioni.
He and his colleagues are only reporting the initial detection from a few orbits in their latest paper. They are working on the analysis of data from about 50 other orbits and more observations will follow.
|Contact: Hkan Svedhem|
European Space Agency