This lovely image of a storm on Saturn is a Twitter picture via SpaceScenery. Click image to make really big.
h/t: Matthew Cobb
A monster storm on Saturn
February 22, 2013 • 3:32 pm
Why Evolution is True is a blog written by Jerry Coyne, centered on evolution and biology but also dealing with diverse topics like politics, culture, and cats.
Mebbe something big came into the atmosphere at a shallow angle??
Unfortunately the Twitter picture is bereft of any details or provenance, but the original, with explanatory text, seems to be here.
My guess is that the storm originates at some relatively fixed point deep in the atmosphere and what we’re seeing is the top layers of it being stripped off and carried around the planet by high winds in the upper atmosphere.
I nearly put my foot into my mouth by suggesting that it’s an image from near the time of a “ring plane crossing”, which happens every 11 or 12 years. As seen from Earth. But for a photo from Cassini, orbiting around the Saturnian system like a bee on LSD, there are probably “ring plane crossings” every few weeks or months. So that’s not a good tool for estimating the date of this event.
Your link does point out that Saturnian storm activity has shifted as Saturn has passed through it’s equinoxes and the sub-solar point (band) has moved from one hemisphere to the other.
Meanwhile, elsewhere on Saturn … a hexagonal storm.
(I don’t actually know what a bee on LSD is like. But I’m sure someone does.)
Fabulous!
Wow… I just can’t seem to find adequate words to say how lucky we are to be able to use science to see these things in our universe…. waaay out there in the great beyond, as well as right there at our very feet.
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Bad Astronomy had a nice piece on this phenomena.
Monster Saturn Storm Chokes on Its Own Tail
“At its peak, it was over 300,000 km (180,000 miles) long—3/4 of the distance from the Earth to the Moon!”
How stunning.
If Saturn is gaseous, why does its atmosphere stop so abruptly, making it a sharp-edged spheroid, and taking those crisp shadows of the rings?
Like the Earth’s upper atmosphere, Saturn’s is stratified by temperature and pressure into layers of distinct gaseous composition. What we see as the visible surface is the boundary between the topmost opaque layer and the outer transparent layers.
The other factor is that atmospheric pressure decreases exponentially with increasing altitude. So even the transparent layers thin out to near vacuum pretty sharply. How quickly? On Saturn the scale height is ~60 km. The planet’s radius is ~60,000 km. So in 1% of its radius (600 km or ten scale heights) the pressure falls off by a factor of e^10 or about 22,000. That’s pretty sharp.