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Post Info TOPIC: Saturn's upper atmosphere


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Saturn
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This image of Saturn was taken by the Cassini spaceprobe on May 22, 2006, when it was approximately 272,307 kilometres away.

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The image was taken using the CB2 and CL2 filters.


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Saturn's Clouds
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The bright whorls and small-scale specks of convective clouds drift through a region just north of Saturn's bright equatorial band. Observers have seen major storms develop in this region in the past 15-20 years.


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The image was taken in visible red light with the Cassini spacecraft narrow-angle camera on March 13, 2006, at a distance of approximately 2.6 million kilometres from Saturn. The image scale is 15 kilometres per pixel.

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RE: Saturn's upper atmosphere
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Saturn rotates approximately once every 10.8 hours -- and its horizontal cloud bands rotate at different rates relative to each other. These conditions can cause turbulent features in the atmosphere to become greatly stretched and sheared, creating the beautiful patterns that the Cassini spacecraft observes. This turbulence and shear is particularly notable at those boundaries where the different bands slide past each other.



Vortices like the one seen here are long-lived dynamical features that are part of the general circulation of Saturn's atmosphere. They are counterparts to the east-west flowing jets and can last for months or years. They probably grow by merging with other vortices until a few dominate a particular shear zone between two jets.

This image was taken in polarised infrared light with the Cassini spacecraft narrow-angle camera on March 7, 2006, at a distance of approximately 2.9 million kilometres from Saturn.
The image scale is 17 kilometres per pixel.

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This image was taken by the Cassini spacecraft on March 05, 2006 and received on Earth March 06, 2006. Saturn was approximately 2,692,707 kilometres away.



The image was taken using the CL1 and CL2 filters.

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Listen to Saturn's Lightning (mp3)

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Saturn's lightning
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Cassini imaging scientists, in search of the large atmospheric Saturnian storm recently detected by its powerful lightning-generated electromagnetic bursts, have found it by looking at the darkside.

the storm was detected by Cassini on January 23, at a latitude that matches that of the "Dragon storm," which was a powerful emitter of radio noise and was imaged by Cassini in 2004.
It lies in a region of the southern hemisphere, at -36 degrees planetocentric latitude and 168 degrees west longitude, that has a high level of storm activity observed there by Cassini. The storm's north-south dimension is about 3,500 kilometres.

No lightning flashes are visible in the images.



The image shows the storm as it appeared to the Cassini imaging system on January 27, 2006.
The views were obtained in visible light with the Cassini spacecraft narrow-angle camera at a distance of approximately 3.5 million kilometres from Saturn. The image scale is 20 kilometres per pixel.

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RE: Saturn's upper atmosphere
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These two comparison images shoe the vortices mingling amidst other turbulent motions in Saturn's atmosphere. The image on the right was taken about two Saturn rotations after the image on the left.


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Both views show latitudes from minus 23 degrees to minus 42 degrees. The region below centre in these images (at minus 35 degrees) has seen regular storm activity since Cassini first approached Saturn in early 2004.
Cassini investigations of the atmosphere from February to October 2004 showed that most of the oval-shaped storms in the latitude region near minus 35 degrees rotate in a counter-clockwise direction, with smaller storms occasionally merging into larger ones.

On Earth, hurricanes in the Southern Hemisphere rotate clockwise. Thus, the storms in these images of Saturn's southern latitudes could be called "anti-hurricanes."
This backwards spiraling (compared to Earth) is common on the giant planets.

The images were taken with the Cassini spacecraft narrow-angle camera on July 4 and 5, 2005, using a filter sensitive to wavelengths of infrared light centred at 750 nanometres. During this time, Cassini's distance from Saturn was approximately 2.4 million kilometres. The image scale is about 14 kilometres per pixel.


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This image was taken by the Cassini spacecraft on July 04, 2005 and received on Earth July 04, 2005.


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The cloud tops of Saturn were approximately 2,361,745 kilometres away. The image was taken using the CL1 and MT2 filters.

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Saturn's rings appear strangely warped in this view of the rings seen through the upper Saturn atmosphere.

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The atmosphere acts like a lens in refracting (bending) the light reflected from the rings. As the rings pass behind the overexposed limb (edge) of Saturn as seen from Cassini, the ring structure appears to curve downward due to the bending of the light as it passes through the upper atmosphere.
This image was obtained using a near-infrared filter.
The filter samples a wavelength where methane gas does not absorb light, thus making the far-off rings visible through the upper atmosphere.
By comparing this image to similar ones taken using filters where methane gas does absorb, scientists can estimate the vertical profile of haze and the abundance of methane in Saturn's high atmosphere.
The image was taken in visible light with the Cassini spacecraft narrow-angle camera on April 14, 2005, through a filter sensitive to wavelengths of infrared light centred at 938 nanometres and at a distance of approximately 197,000 kilometres from Saturn. The image scale is 820 metres per pixel.


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