London: An ozone layer high in the Venusian atmosphere has been discovered by a European Space Agency (ESA) probe.
Comparing its properties with those of the equivalent layers on Earth and Mars will help astronomers refine their search for life on other planets.
The space probe, Venus Express, made the discovery while watching stars seen right at the edge of the planet set through its atmosphere.
The ozone -- which has a molecule containing three oxygen atoms -- was detectable because it absorbed some of the ultraviolet rays from the starlight, reports the journal Icarius.
According to computer models, the ozone on Venus is formed when sunlight breaks up carbon dioxide molecules, releasing oxygen atoms, according to an EPA statement.
"This detection gives us an important constraint on understanding the chemistry of Venus` atmosphere," says Franck Montmessin, of the ESA, who led the research.
It may also offer a useful comparison for searching for life on other worlds. Ozone has only previously been detected in the atmospheres of Earth and Mars.
"This ozone detection tells us a lot about the circulation and the chemistry of Venus`s atmosphere" says Håkan Svedhem, ESA project scientist for the Venus Express mission.
The results are being presented at the Joint Meeting of the European Planetary Science Congress and the American Astronomical Society`s Division for Planetary Sciences.