[meteorite-list] Cassini Spacecraft Sees Huge Burp At Saturn After Large Storm

[Ron Baalke]

Oct. 25, 2012

Dwayne Brown 
Headquarters, Washington 
202-358-1726 
dwayne.c.brown at nasa.gov 

Elizabeth Zubritsky/Nancy Neal-Jones 
Goddard Space Flight, Center, Greenbelt, Md. 
301-614-5438/301-286-0039 
elizabeth.a.zubritsky at nasa.gov/nancy.n.jones at nasa.gov 

Jia-Rui C. Cook 
Jet Propulsion Laboratory, Pasadena, Calif. 
818-354-0850 
jccook at jpl.nasa.gov 


RELEASE: 12-375

NASA SPACECRAFT SEES HUGE BURP AT SATURN AFTER LARGE STORM

WASHINGTON -- NASA's Cassini spacecraft has tracked the aftermath of a 
rare massive storm on Saturn. Data reveal record-setting disturbances 
in the planet's upper atmosphere long after the visible signs of the 
storm abated, in addition to an indication the storm was more 
forceful than scientists previously thought. 

Data from Cassini's composite infrared spectrometer (CIRS) instrument 
revealed the storm's powerful discharge sent the temperature in 
Saturn's stratosphere soaring 150 degrees Fahrenheit (83 kelvins) 
above normal. At the same time, researchers at NASA's Goddard 
Spaceflight Center in Greenbelt, Md., detected a huge increase in the 
amount of ethylene gas, the origin of which is a mystery. Ethylene, 
an odorless, colorless gas, isn't typically observed on Saturn. On 
Earth, it is created by natural and man-made sources. 

Goddard scientists describe the unprecedented belch of energy in a 
paper to be published in the Nov. 20 issue of the Astrophysical 
Journal. 

"This temperature spike is so extreme it's almost unbelievable, 
especially in this part of Saturn's atmosphere, which typically is 
very stable," said Brigette Hesman, the study's lead author and a 
University of Maryland scientist who works at Goddard. "To get a 
temperature change of the same scale on Earth, you'd be going from 
the depths of winter in Fairbanks, Alaska, to the height of summer in 
the Mojave Desert." 

First detected by Cassini in Saturn's northern hemisphere on Dec. 5, 
2010, the storm grew so large that an equivalent storm on Earth would 
blanket most of North America from north to south and wrap around our 
planet many times. This type of giant disturbance on Saturn typically 
occurs every 30 Earth years, or once every Saturn year. 

Not only was this the first storm of its kind to be studied by a 
spacecraft in orbit around the planet, but it was the first to be 
observed at thermal infrared wavelengths. Infrared data from CIRS 
allowed scientists to take the temperature of Saturn's atmosphere and 
to track phenomena that are invisible to the naked eye. 

Temperature measurements by CIRS, first published in May 2011, 
revealed two unusual beacons of warmer-than-normal air shining 
brightly in the stratosphere. These indicated a massive release of 
energy into the atmosphere. After the visible signs of the storm 
started to fade, CIRS data revealed the two beacons had merged. The 
temperature of this combined air mass shot up to more than minus 64 
degrees Fahrenheit (above 220 kelvins). 

According to Hesman, the huge spike of ethylene generated at the same 
time peaked with 100 times more ethylene than scientists thought 
possible for Saturn. Goddard scientists confirmed the release of the 
gas using the Celeste spectrometer mounted on the McMath-Pierce Solar 
Telescope on Kitt Peak in Arizona. 

The team still is exploring the origin of the ethylene, but has ruled 
out a large reservoir deep in the atmosphere. 

"We've really never been able to see ethylene on Saturn before, so 
this was a complete surprise," said Goddard's Michael Flasar, the 
CIRS team lead. 

A complementary paper led by Cassini team associate Leigh Fletcher of 
Oxford University, England, describes how the two stratospheric 
beacons merged to become the largest and hottest stratospheric vortex 
ever detected in our solar system. Initially, it was larger than 
Jupiter's Great Red Spot. 

Their paper in the journal Icarus, which combines CIRS data with 
additional infrared images from other Earth-based telescopes, 
including NASA's Infrared Telescope Facility at Mauna Kea, Hawaii, 
also reports a powerful collar of clockwise winds -- encompassing a 
bizarre soup of gases -- around the vortex. 

"These studies will give us new insight into some of the photochemical 
processes at work in the stratospheres of Saturn, other giants in our 
solar system, and beyond," said Scott Edgington, Cassini deputy 
project scientist at NASA's Jet Propulsion Laboratory (JPL) in 
Pasadena, Calif. 

The Cassini-Huygens mission is a cooperative project of NASA, the 
European Space Agency, and the Italian Space Agency. The mission is 
managed by JPL for NASA's Science Mission Directorate in Washington. 
Hesman's work was funded in part by NASA's Planetary Astronomy 
Program in Washington. The CIRS instrument and Celeste spectrometer 
were built at Goddard. 

To read more about the Fletcher paper, visit: 

http://www.esa.int/esaSC/SEMLPIMFL8H_index_0.html 

For information about Cassini and this observation, visit: 

http://www.nasa.gov/cassini 
	
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