Rapid Changes on Saturn’s Moon
December 12, 2012 in Outdoors
Study: Autumn sets in rapidly on Saturn’s moon Titan
Titan, seen during Cassini’s Mar. 31, 2005, flyby
Thanks to NASA’s Cassini spacecraft which has been orbiting Saturn since 2004, scientists have been able to observe for the first time ever the seasonal atmospheric circulation direction change on Titan – an event which only happens once every 15 years and is never observable from Earth. Their findings are published today in Nature
Titan, while technically only a moon, is bigger than the planet Mercury, and is often considered a planet in its own right. It is the only known moon to have a significant atmosphere and is one of only four terrestrial atmospheres in our Solar System (the other three being Earth, Venus, and Mars). As Titan’s rotation axis is tilted by a similar amount to that of the Earth, it experiences seasons in a similar way, but at a much more relaxed pace as Saturn takes 29.5 Earth years to orbit the Sun.
Dr Nick Teanby of the University of Bristol and colleagues used infrared spectra measured by Cassini’s Composite InfraRed Spectrometer (CIRS) instrument to determine atmospheric temperature and global distributions of chemical tracers. This allowed them to map out the seasonal changes in great detail.
The team observed an enormous increase in Titan’s exotic trace gases over the south pole within a relatively short time. These trace gases are produced high in Titan’s atmosphere, where sunlight and highly energetic particles break down nitrogen and methane and recombine to form a vast array of more complex molecules like benzene and hydrogen cyanide.
This true color image captured by NASA’S Cassini spacecraft before a distant flyby of Saturn’s moon Titan on June 27, 2012, shows a south polar vortex, or a mass of swirling gas around the pole in the atmosphere of the moon. Credit: NASA/JPL-Caltech/Space Science Institute
Co-author, Dr Remco de Kok of SRON Netherlands Institute for Space Research said: “We were waiting for signs that the trace gas abundances would change together with the new season, but we did not expect such a large and rapid change: some gas concentrations increased more than a thousand times within only a few months. Also surprising was that this was happening at altitudes above 450 km, much higher than initially anticipated.”
Read more at: http://phys.org
“Our results provide a powerful new constraint for atmospheric models of Titan. Titan provides a natural laboratory for an Earth-like atmosphere in the cold outer solar system…” http://phys.org Titan is Proto-Earth #5