APOD: Io over Jupiter from Voyager 1 (2016 Sep 04)

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APOD: Io over Jupiter from Voyager 1 (2016 Sep 04)

Postby APOD Robot » Sun Sep 04, 2016 4:09 am

Image Io over Jupiter from Voyager 1

Explanation: Back in 1979, NASA's Voyager 1 spacecraft flew past Jupiter and its moons. The images in this mosaic, featuring the moon Io against a background of gas giant Jupiter's diffuse swirling cloud bands, were recorded by Voyager's camera from a distance of about 8.3 million kilometers. The Io image from this mosaic may be the first to show curious round features on Io's surface with dark centers and bright rims more than 60 kilometers across. Now known to be volcanic in origin, these features were then thought likely to be impact craters, commonly seen on rocky bodies throughout the Solar System. But as Voyager continued to approach Io, close-up pictures revealed a bizarre world devoid of impact craters, frequently resurfaced by volcanic activity. Earlier this year a new robotic spacecraft, NASA's Juno, began to orbit Jupiter and last week made a pass within 5,000 kilometers of Jupiter's clouds. During the next two years, it is hoped that Juno will discover new things about Jupiter, for example what's in Jupiter's core.

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Re: APOD: Io over Jupiter from Voyager 1 (2016 Sep 04)

Postby Boomer12k » Sun Sep 04, 2016 4:09 am

And still so much to learn....

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Ann
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Re: APOD: Io over Jupiter from Voyager 1 (2016 Sep 04)

Postby Ann » Sun Sep 04, 2016 4:46 am

Ah, the beauty of Jupiter. What a great photo this old Voyager image is. And what a pity that Juno is apparently not going to give us anything like that kind of photos.

Nevertheless, Juno will undoubtedly give us a lot of new information about Jupiter, and I'm eagerly waiting for it.

Ann
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RocketRon

Re: APOD: Io over Jupiter from Voyager 1 (2016 Sep 04)

Postby RocketRon » Sun Sep 04, 2016 6:28 am

What is the current line of thinking as to why Jupiter's atmosphere
hasn't been thoroughly blended into a homogeneous mix by now ?

heehaw

Re: APOD: Io over Jupiter from Voyager 1 (2016 Sep 04)

Postby heehaw » Sun Sep 04, 2016 8:46 pm

RocketRon wrote:What is the current line of thinking as to why Jupiter's atmosphere
hasn't been thoroughly blended into a homogeneous mix by now ?

Complex business! Why do we on Earth have clouds some places some times and not other places other times, or, well, you know what I mean!?

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Re: APOD: Io over Jupiter from Voyager 1 (2016 Sep 04)

Postby neufer » Sun Sep 04, 2016 9:06 pm

RocketRon wrote:
What is the current line of thinking as to why Jupiter's atmosphere hasn't been thoroughly blended into a homogeneous mix by now ?

    It is spinning too fast.
:arrow: Our slower rotation rate divides our atmosphere into ~6 (mostly unmixed) cells.

Jupiter's fast rotation rate divides the Jovian atmosphere into many more (mostly unmixed) cells.
Art Neuendorffer

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Re: APOD: Io over Jupiter from Voyager 1 (2016 Sep 04)

Postby astrokmb » Sun Sep 04, 2016 11:51 pm

I would love to see a side-by-side, to-scale image showing how large the Earth would appear from 8.3 million km compared to this image of Jupiter (taken from 8.3 million km). What a great way that would be to illustrate the enormity of this magnificent planet.

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Re: APOD: Io over Jupiter from Voyager 1 (2016 Sep 04)

Postby Wolf » Mon Sep 05, 2016 1:09 am

Ann wrote:Ah, the beauty of Jupiter. What a great photo this old Voyager image is. And what a pity that Juno is apparently not going to give us anything like that kind of photos.

Nevertheless, Juno will undoubtedly give us a lot of new information about Jupiter, and I'm eagerly waiting for it.

Ann



Ann,
If we could Pantropy in as Clifford D. Simak wrote in 1944, what would be the color of the Jovian sky from the “surface”?

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Re: APOD: Io over Jupiter from Voyager 1 (2016 Sep 04)

Postby Ann » Mon Sep 05, 2016 5:37 am

Wolf wrote:
Ann wrote:Ah, the beauty of Jupiter. What a great photo this old Voyager image is. And what a pity that Juno is apparently not going to give us anything like that kind of photos.

Nevertheless, Juno will undoubtedly give us a lot of new information about Jupiter, and I'm eagerly waiting for it.

Ann



Ann,
If we could Pantropy in as Clifford D. Simak wrote in 1944, what would be the color of the Jovian sky from the “surface”?


Like this?

Click to play embedded YouTube video.

Wikipedia wrote:

Jupiter has the largest planetary atmosphere in the Solar System, spanning over 5,000 km (3,000 mi) in altitude.[46][47] Because Jupiter has no surface, the base of its atmosphere is usually considered to be the point at which atmospheric pressure is equal to 100 kPa (1.0 bar).


According to Wikipedia, the height of Jupiter's atmosphere is 5,000 km. What would be the color of the sky from the bottom of an extremely thick and cloudy 5,000 km high atmosphere? Pitch black, I would say.

Okay, what would be the color of the Jovian sky near its cloud tops? Well, it just might be the same color as most of the clouds, which mostly range from creamy white to light brick orange. Or else, who knows, it might be pitch black interspersed with a generous sprinkling of stars.

Does Jupiter have a blue sky anywhere? All I can say about it is that I have never seen a picture suggesting that it does. That doesn't necessarily mean there isn't a blue sky at some upper level of the atmosphere of Jupiter.

Saturn. Image credit: Cassini Imaging Team, SSI, JPL, ESA, NASA
Pluto. Image credit: NASA/JHUAPL/SwRI

























Whether or not Jupiter has any sort of blue sky anywhere in its atmosphere, both Saturn and Pluto do have some sort of blue skies.

APOD Robot wrote about Saturn:

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.


The same mechanism must be responsible for making Pluto's atmosphere blue. It wouldn't surprise me if some thin upper part of Jupiter's atmosphere has the same property and color.

Ann
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Re: APOD: Io over Jupiter from Voyager 1 (2016 Sep 04)

Postby DavidLeodis » Mon Sep 05, 2016 1:27 pm

There is more information about this lovely image in the Solaris section. This is the link to the image and its information: https://www.flickr.com/photos/alex-is-solaris/28632019403/

RocketRon

Re: APOD: Io over Jupiter from Voyager 1 (2016 Sep 04)

Postby RocketRon » Tue Sep 06, 2016 1:32 am

On planet Earth, any large scale volcanic activity in the equatorial region puts a deposit of ash in
both Antarctica and Greenland icesheets.

That would imply a fair bit of atmospheric mixing. ?
The CO2 and methane and fluorocarbon/ozone etc levels also would indicate this, allowing for transient local concentrations. ??

Even with just a trace of inter-mixing with the high wind speeds on Jupiter, over millions (billions ?) of years, would we expect to see the bands on Jupiter still so clearly defined ?


neufer wrote:

    It is spinning too fast.
:arrow: Our slower rotation rate divides our atmosphere into ~6 (mostly unmixed) cells.

Jupiter's fast rotation rate divides the Jovian atmosphere into many more (mostly unmixed) cells.


RocketRon wrote:
What is the current line of thinking as to why Jupiter's atmosphere hasn't been thoroughly blended into a homogeneous mix by now ?

Laurent Allen-Guérard

Re: APOD: Io over Jupiter from Voyager 1 (2016 Sep 04)

Postby Laurent Allen-Guérard » Thu Sep 08, 2016 2:24 am

It really seem to me that the stripe below the moon has it's size. Then I found this article http://www.sciencemag.org/news/2010/05/how-jupiter-got-its-stripes. What do you think of the moon having influence on the gas below?

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Re: APOD: Io over Jupiter from Voyager 1 (2016 Sep 04)

Postby rstevenson » Thu Sep 08, 2016 12:59 pm

RocketRon wrote:... Even with just a trace of inter-mixing with the high wind speeds on Jupiter, over millions (billions ?) of years, would we expect to see the bands on Jupiter still so clearly defined ?

I think you're conceptualising this as: first there were bands, then mixing occurred, so there shouldn't be bands now. But I see the bands as being analagous to standing waves. Whatever mixing is occurring, there will still be bands, because the forces that produce them continue. No doubt the bands are evolving over time, but they continue. And the strongest evidence for evolving bands is that we see them today, more than 4 billion years after the planet began to form.

Rob


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