Skip to comments.Astronomy Picture of the Day -- Saturn in Blue and Gold
Posted on 04/12/2014 9:33:33 PM PDT by SunkenCiv
Explanation: Why is Saturn partly blue? The above picture of Saturn approximates what a human would see if hovering close to the giant ringed world. The above picture was taken in 2006 March by the robot Cassini spacecraft now orbiting Saturn. Here Saturn's majestic rings appear directly only as a thin vertical line. The rings show their complex structure in the dark shadows they create on the image left. Saturn's fountain moon Enceladus, only about 500 kilometers across, is seen as the bump in the plane of the rings. The northern hemisphere of Saturn can appear partly blue for the same reason that Earth's skies can appear blue -- molecules in the cloudless portions of both planet's atmospheres are better at scattering blue light than red. When looking deep into Saturn's clouds, however, the natural gold hue of Saturn's clouds becomes dominant. It is not known why southern Saturn does not show the same blue hue -- one hypothesis holds that clouds are higher there. It is also not known why Saturn's clouds are colored gold.
(Excerpt) Read more at 18.104.22.168 ...
[Credit: Cassini Imaging Team, SSI, JPL, ESA, NASA]
Thanks for posting these links. I enjoy them and often forward them to kids.
Thanks for the picture.
Sure, but it’s not the pure blue that you see in the north.
It occurs to me that since the sun is shining from the south, the illumination near the north and south poles is quite different, and one may certainly imagine that if the planet were tilted the other way, we would see the bluer appearance in the south.
It seems a simple point!
Well, it takes 15 years to go from one tilt to the other, and Cassini has been there for ten years, since 2004. Saturn was at equinox in September 2009, so the illumination right now is comparable to the illumination at arrival, with north and south switched. I guess this means that the comparison can be made, but it seems that the description we are given doesn’t address this question.
That occurred to me as well. The sunlight is hitting the north pole at a lower angle this time of “year”, and when you see a red sunset it’s partly because more blue light is being scattered due to the low angle. It’s shining through the greatest amount of atmosphere possible. But since I don’t work for NASA, I admit the maybe 0.2% possibility that I don’t have all the facts in order.
BTW, have you ever seen “blue sky” below the horizon? I have noticed this on one or two airline flights that I took years ago. It made sense to me at the time on the basis that the real requirement was a line of sight through tens of miles of illuminated atmosphere. From the ground, you have to be looking at the “sky” to get this effect, but several miles in the air, the boundary between earth and sky becomes ambiguous.
"Alas! We only live through 500 revolutions around the sun," said the Saturnian. (This translates to about 15,000 years, by our standards.) "You can see yourself that this is to die almost at the moment one is born; our existence is a point, our lifespan an instant, our planet an atom. Hardly do we begin to learn a little when death arrives, before we get any experience. As for me, I do not dare make any plans. I see myself as a drop of water in an immense ocean. I am ashamed, most of all before you, of how ridiculously I figure in this world."
Or wait a minute, do you mean you’re seeing blue sky from the air while looking down? That does make sense, actually. Interesting too. Rayleigh scattering goes in all directions, but we’re accustomed to seeing it coming down, not up.
It’s so people can say, “blue hoo to you too”.
Yeah, that’s it. I would see sky blue patches looking toward the horizon, but below it.
Scientists do not know why Saturn’s clouds are gold? Hmmm... Aliens?
Did any of them try to do a spectrographic analysis, in the last 50-60 years, of the clouds to find their composition?
My bare eye says that the planet is blue in the north, gold at the equator, and slightly less gold and slightly bluish
in the southern latitudes. But the south pole segues back to gold.
:’) I rode in one of those yesterday, but white exterior, gray interior. Well, gray and debris interior, it’s always nice to see someone else who has the same house/car-keeping skills as me.
:’) Obviously we need to send another probe. It’s only fair, those darned aliens are always probing Earthlings...
Amazing how well organized those rings are.
My Saturns have been white(3) and green(1).
Goodness, you’re right. It’s about time the aliens started pulling their own weight around our solar system.
This thread is tending towards Hue & Sirius ....
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