Venus has an ozone layer
12 Oct 2011 by Evoluted New Media
An ozone layer has been discovered high up in the atmosphere of Venus by the European Space Agency’s Venus Express spacecraft.
Venus’ ozone layer sits at an altitude of 100 km – about four times higher in the atmosphere than Earth’s – and is a hundred to a thousand times less dense. By comparing its properties with those of the equivalent ozone layers on Earth and Mars, astronomers hope to refine their search for life on other planets.
Venus Express made the discovery while watching stars right at the edge of the planet set through its atmosphere. Its SPICAV instrument looked for characteristic fingerprints of gases in the atmosphere as they absorbed light at different wavelengths – ozone was detectable because it absorbed some ultraviolet emanating from the starlight.
Computer models suggest the ozone is formed when sunlight breaks up carbon dioxide, releasing oxygen atoms which are then swept around to the nightside of the planet by winds in the atmosphere. These then combine to form oxygen atoms, and sometimes ozone.
“This detection gives us an important constraint on understanding the chemistry of Venus’ atmosphere,” said Frank Montmessin, who led the research.
The discovery of ozone might also offer a useful comparison for searching for life on other worlds – some astrobiologists suggest that the simultaneous presence of oxygen, ozone and carbon dioxide in an atmosphere could be used to tell whether there could be life on the planet. Indeed, Montmessin says these new observations can be used to test and refine the scenarios for detecting life on other worlds.
“This ozone detection tells us a lot about the circulation and chemistry of Venus’ atmosphere,” said Håkan Svedhem, ESA project scientist for the Venus Express mission. “Beyond that, it is yet more evidence of the fundamental similarity between the rocky planets, and shows the importance of studying Venus to understand them all.”
