Yes, Virginia -- Venus Has an Ozone Layer

Yes, Virginia, Venus does have an ozone layer -- and the finding could help astronomers better target their search for life on other planets.

The planet's thin ozone layer, discovered by the European Space Agency's Venus Express craft, was identified when the orbiting vehicle was looking closely at stars through the Venusian atmosphere, according to a report by researchers in the journal Icarus.

It is the first detection of ozone in the atmosphere of Venus, and the finding indicates that the key chemical reactions operating in Earth's upper stratosphere may also operate on Venus, according to the report.

Ozone has previously only been detected in the Earth's atmosphere and Mars' atmosphere. Ozone is critical to life on Earth, because it absorbs harmful rays from the sun, which otherwise would be deadly for humans. Scientists say the buildup of oxygen in the Earth's atmosphere began roughly 2.4 billion years ago.

Ozone is a molecule that contains three oxygen atoms.

The Earth's layer of ozone is a result of the large abundance of molecular oxygen in our planet's atmosphere. When irradiated by solar ultraviolet rays, oxygen molecules are broken into atoms. The atoms react with other oxygen molecules to create protective ozone.

The ozone layer found on Venus is an estimated 1,000 times less dense than the Earth's ozone layer. Astronomers had theories that ozone was present around Venus, but before the recent finding it had never been found in the planet's atmosphere. But now, because the thin ozone layer has been found, astronomers have new constraints for the search of biomarkers on extraterrestrial planets, the report said.

We can use these new observations to test and refine the scenarios for the detection of life on other worlds, said Dr. Frank Montmessin, of the LATMOS atmospheric research center in France, lead author of the report paper.

The discovery provides future hints for planetary systems beyond our own, which will lead to more in-depth search and study for other elements associated with living organisms, including water, carbon dioxide, and molecular oxygen.

We were surveying the atmosphere of Venus and focusing on other molecules when we stumbled on a very interesting feature in one of the spectra, said Montmessin. The spectral signature of ozone, a distinctive absorption band at [ultraviolet] wavelengths, was rather pronounced and we could clearly discern it in our plots with the naked eye.