Details of Vortex at Saturn's Southern Pole (APOD 13 Nov 06)

[pigscott]

The active hurricane @ Saturn's south pole (13/11/2006) is awesome as an mpeg. Download it APOD fans. Cassini sends the best pictures from the farthest places. Why will this storm persist forever? Because it's trapped at an axis which itself is swirling?
pigscott

[Dana McPeek]

Since ths hurricane on Saturn's south pole is thought to be permanent, is there a similar one on Jupiter? Has anyone looked?
D

[iamlucky13]

I think checked out the poles on Jupiter and found nothing like this, but they did find that Jupiter has polar auroras.

I'm curious if this effect is occuring at Saturn's north pole, too.

[ipaine]

What is the depth of the vortex at the different visable layers clouds? or at least the the bottom of what we see?

[Nereid]

Threads merged.

[Qev]

What is the depth of the vortex at the different visable layers clouds? or at least the the bottom of what we see?

Not sure what the depth is, but the tower clouds around the 'eye' are apparently 30 to 75 km taller than the clouds in the very center.

[Dana McPeek]

... and the description said that it was roughly the diamter of Earth. (5,000 miles)
D

[Dana McPeek]

It's been a long time, but I believe that Saturn's clouds, at the surface are VERY dense and under high pressure. Upward of 1 million bars!

As I remember, most of the atmosphere is made up of hydrogen and helium, with amonia toward the top. If the diameter of the opening is 5000 miles, and the walls are traveling at 550 mph, I would think that the cone would be very steep. If so, the depth could be as much as 5000-8000 miles to the bottom of the cone.

Hydrogen, under pressure will act like a fluid. At the tops, it will be very thin and contain amonia which causes the orange color. As it gets deepr and denser, the speed will increase - the vortex will narrow... I think

D

[ipaine]

Isa Paine

[ipaine]

Thank you for your replies.

Then what do we see at the bottom, hydrogen?

Isa Piane

[Dana McPeek]

Probably only amonia, other traces gases, and helium. I doubt that the vortex goes anywhere deep enough to get to layers that are hydorgen in a fluid state.

For that matter, is the interior of the vortex a vacuum?
D

[iamlucky13]

Probably not. Probably just a lower density, like a hurricane on earth. The potential difference between the pressures you describe and an absolute vacuum is huge! (actually, I think a million bars is inconsistent with Saturn's overall density, but I've read the pressure is very high compared to what we're familiar with). Even a fierce tornado only represents a difference of a psi or so.

Also, it sounds like the vortex as a whole is 5000 miles in diameter, not just the opening, which would obviously be smaller...unless I read the caption wrong.

[Dana McPeek]

"...it sounds like the vortex as a whole is 5000 miles in diameter, not just the opening, which would obviously be smaller..."?

To measure a vortex by it's volume, rather than it's opening, seems like an odd and difficult way to measure.

The caption reads "The storm is slightly larger than the entire Earth and carries winds that reach 550 kilometers per hour" That would have to mean the opening at tthe top is larger than 5000 miles.

As to bars of preasure, check the encyclopedia. I did. It's a scruntchy 1 million bars at the surface.

D

[Bill McDill]

I would swear that there is a spot at about 7 O'clock near the edge of the eye that looks like a crater- can't be but sure is interesting.

[BMAONE23]

That is interesting. there are two more at the 2:30 side too both inside the eye and on the rim.
http://antwrp.gsfc.nasa.gov/apod/ap061113.html

[Dana McPeek]

NASA Fact Sheet:
Saturnian Atmosphere

Surface Pressure: >>1000 bars
Temperature at 1 bar: 134 K (-139 C)
Temperature at 0.1 bar: 84 K (-189 C)
Density at 1 bar: 0.19 kg/m3
Wind speeds
Up to 400 m/s (<30 degrees latitude)
Up to 150 m/s (>30 degrees latitude)
Scale height: 59.5 km
Mean molecular weight: 2.07 g/mole
Atmospheric composition (by volume, uncertainty in parentheses)
Major: Molecular hydrogen (H2) - 96.3% (2.4%); Helium (He) - 3.25% (2.4%)
Minor (ppm): Methane (CH4) - 4500 (2000); Ammonia (NH3) - 125 (75);
Hydrogen Deuteride (HD) - 110 (58); Ethane (C2H6) - 7 (1.5)
Aerosols: Ammonia ice, water ice, ammonia hydrosulfide



I stand corrected on my 1 million bars. Nasa says 1000 bars.
Height of the atmosphere is 59.5 km, 37 miles deep.

Assuming the mouth is 5000 miles across, the depth of the vortex could be as much as_________?
D

[Dana McPeek]

You're asking me??? They found it just last week...

(but I would assume so...)

D

[Charles Wilson]

One of the most astounding pictures I have ever seen!

Looking straight down the pipe are some blurry, smudgy white things.

Any ideas on what they are? Any ideas? At all?

Charles

[Andy Wade]

One of the most astounding pictures I have ever seen!

Looking straight down the pipe are some blurry, smudgy white things.

Any ideas on what they are? Any ideas? At all?

Charles

Hi Charles,

Yes, it has a 'frightening' aspect to it when you realise just how large it is.

If you look at the video version (linked from the APOD Vortex page) you can just make out a little bloke with one of those battery operated personal fans...

Seriously though, there are lots of white swirls in the atmosphere, some of which can be seen in the video version, I expect these are just more of the same. There's a big one at the 'top' side of the vortex as viewed in the picture.
I'm guessing on this point, but If this vortex works the same way as a tornado works here on earth, then the wind direction inside it is generally upwards, so maybe it's bringing lower level gases to the surface?

[Charles Wilson]

The neat thing about the "smudgy, white things" is that they orbit within the elliptical distortions in which they are anchored. With the Eye Wall very close to circular in spite of the mass distortions, we have a very tantalizing physics workshop.

What forces would keep several "columns" orbiting a center and yet not be strong enough to significantly distort the eyewall?

CW

[BMAONE23]

interesting thing about the movie http://ciclops.org/media/ir/2006/2313_6310_4.mpg
at the beginning there is a bright flash (lightning) at 12:00 near the circular eyewall and then again at 7:30 near the end of the movie. The white blobs could be thunderstorms.

[Doum]

Very interesting BMAONE33,

By slowly moving the cursor backward u can count many bright flash for each picture. I count more then 15. Big lightning if its what they are.

[Wadsworth]

What is the time laps of this video?
The 'lightning' flashes are relatively motionless when compared to the upper atmosphere (they seem to be well below the quickly revolving gas). This can be seen well if you have a viewer with a 'step' function.

Also, why does it seem as though frames are missing from the clip? As its speed varies violently.


Furthermore, slowing the video to 1/4 speed makes the 'lightning' flash durations comparable to those here on earth. Then if a circumferential path measurement is taken of one of the blobs, particularly one at 11 o'clock on the ring where the color transitions from dark to light grey, using only the first for seconds of video (1 second at actual speed) in order to eliminate the 'missing frames'.
The blob traverses .1389 km/s at 500 km/hr so it travels roughly .5556 km in this slowed four second clip. Put to scale that makes the diameter of the larger dark disk (where largest color contrast occurs, or about 2/3 of the video longitude) only 12.69 km.

So either:

A) The winds are much faster.
B) The Large grey disk or secondary 'eye' is not what they referred to as being earth size.
C) The lightning flash durations are 1000 times longer than here on earth.
D) They aren't lightning flashes.