Mysterious Titan has a Ghostly Dawn to Dusk Glow
Mysterious Titan has a Ghostly Dawn to Dusk Glow
Oct 22, 2014 03:02 PM ET // by Ian O'Neill
It’s as if Titan is getting festive for Hallowe’en.
Astronomers have detected a ghostly glow around the the north and south poles of the Saturnian moon that had previously gone undetected. Caused by emissions from two trace gases, their locations are shifted off the poles along the dawn-dusk (east-west) line, and researchers are stumped as to why there’s an abundance of these gases at such high altitudes and why they have this strange morphology.
“This is an unexpected and potentially groundbreaking discovery,” said astrochemist Martin Cordiner, of NASA’s Goddard Space Flight Center in Greenbelt, Md., and lead author of a paper published today (Oct. 22) in the Astrophysical Journal. “These kinds of east-to-west variations have never been seen before in Titan’s atmospheric gases. Explaining their origin presents us with a fascinating new problem.”
Through highly sensitive observations by the Atacama Large Millimeter/submillimeter Array (ALMA) in Chile, Cordiner’s team was able to take a 3-minute ‘snapshot’ of the chemical signatures of hydrogen isocyanide (HNC) and cyanoacetylene (HC3N) — two compounds that are known to be concentrated in Titan’s lower polar atmosphere. NASA’s Cassini spacecraft that is currently orbiting Saturn has confirmed this by detecting cloud caps above the north and south poles abundant in HNC and HC3N.
But the weird thing is the clouds of gas are shifted off the poles at high altitudes, and this conflicts with our understanding about how Titan’s atmosphere should work. In Titan’s middle atmosphere, powerful east-west winds create zones of mixed gases, much like Jupiter’s familiar banded appearance, only on a smaller scale. These high altitude cloud features are distinct and not mixed, something scientists cannot yet explain.
More:
http://news.discovery.com/space/mysterious-titan-has-a-ghostly-glow-from-dawn-to-dusk-141022.htm#mkcpgn=rssnws1
