Cassini has found Titan’s upper atmosphere to consist of a surprising number of layers of haze, as shown in this ultraviolet image of Titan’s night-side limb, colourised to look like true colour. The many fine haze layers extend several hundred kilometres above the surface. Although this is a night side view, with only a thin crescent receiving direct sunlight, the haze layers are bright from light scattered through the atmosphere. The image was taken with the Cassini spacecraft narrow angle camera. Image credit: Nasa/JPL/Space Science Institute
An international team of scientists has announced the confirmation of a key chemical reaction that forms the molecule triacetylene in the ultra-cold atmosphere of Saturn’s moon Titan.
Since Titan’s current atmosphere is thought to resemble Earth’s early atmosphere, the researchers’ study suggests triacetylene may have been formed in Earth’s early atmosphere and offers clues to the evolution of Earth’s atmosphere before the development of life some 3,5 billion years ago.
The team presents their findings in the 14 September 2009 advance online issue of the Proceedings of the National Academy of Sciences. Funding for the study was provided by the National Science Foundation (NSF).
Triacetylene is member of the polyyne family of compounds. Polyynes are thought to serve as an ultraviolet radiation shield in planetary environments, thus acting as prebiotic ozone, and as important components of the orange-coloured and aerosol-based haze shrouding Titan.
Scientists have been researching the role of triacetylene, as well as the polyyne diacetylene, in the chemical evolution of Titan’s atmosphere for the last four decades.