NeKto      

05-09-2008   14:48:17

It seams the most common things we see in the universe are either rotating discs or rotating spheroids. Has anyone found an answer for where the angular momentum came from?

Red_dragon      

05-09-2008   07:21:46

Thanks; i was suspecting the difference was precissely the great difference in the mass distribution between a galaxy and Saturn's ring system. Anyway, it's beautiful to see similar physical processes working at scales so different as planetary ones and galactic ones.

carolyn      

05-06-2008   13:37:05

The physics is almost identical. The big difference is that in a spiral galaxy, the mass is distributed more or less evenly across the disk, making for a spiral arm with a big wavelength (ie, big separation from one winding to the other). In Saturn's rings, the vast bulk of the mass in the dynamical system is in the planet itself, with very little mass in the disk, and this makes for a much tighter winding. This is why we can learn about disk systems throughout the cosmos -- regardless of size -- by studying the processes ongoing in Saturn's rings.

Red_dragon      

05-06-2008   03:23:42

Just one question: are those "spiral waves" the same that are responsable for shaping spiral galaxies?

alwolfe      

05-05-2008   13:42:09

Lovely visualization of the "music of the spheres." I look forward to seeing the published paper.

carolyn      

05-05-2008   09:42:02

alwolfe: We are presently writing a paper cataloguing all the resonances which are visible in our images. It will be a while before we finish it and get it published.

alwolfe      

05-05-2008   09:26:47

Which resonances are behind the waves in this image?

Red_dragon      

05-05-2008   07:07:12

The patterns nature can create are nothing less than breathtaking and this image shows it quite well.

ulyana      

05-05-2008   16:43:31

Hello, Andrew. I would say there is not much doubt about water ice particles, though there is ammonia on Jupiter and Saturn to precipitate as well as water. It may play a role. Lightning on Uranus and Neptune is not detected but expected. There is definitely the uncertainty about convection and observing lightning on the night side of Jupiter turns out to be a great tool in figuring out were the convection occurs. On Saturn strong updrafts shown in the figures above appear to be stronger and way less frequent than on Jupiter. The power is hard to compare because on Jupiter we estimate the optical power and have no radio data, and on Saturn there is no optical data but there is radio detections to estimate the power. And yes the updrafts are probably higher on Saturn.

3488      

05-05-2008   15:45:52

Hi ulyana, There would be no doubt that the lightning in all four of the outer planets (Jupiter to Neptune) is generated by the charge generated though ice crystals, as on Earth. The uncertainty lies with the exact mechanism of how internal heat particularly with Jupiter, Saturn & Neptune convects the atmosphere & the relationships with the ice & other compounds, how they may contribute to lightning generation. Almost certainly Jupiter, Saturn, Uranus & Neptune have rain, snow & hail, possibly giant hail (I saw something once that suggested that Jupiter, Saturn & Neptune could have hailstones the size of footballs, don't know if that is still thought to be so). The Galileo spacecraft saw thunderheads rise 50 KM or more above the general cloud deck in Jupiter's atmosphere. Don't know about Saturn, although with Saturn, the thunderheads should rise even higher due to the much weaker gravity, unbless the updraghts are weaker than Jupiter's. Andrew Brown.

ulyana      

05-05-2008   12:47:43

The mechanism of lightning generation on Saturn and Jupiter is not completely understood. However both planets are expected to have water clouds, which are the best candidates for lightning generation. If this is the case, lightning generation should be similar to the one in terrestrial thunderstorms - by separation of charges carried by hail, rain, and ice particles falling down at different speeds.

Red_dragon      

04-30-2008   02:23:06

Great stuff. It seems the famous "Dragon Storm" has returned.

vista      

04-29-2008   17:32:53

a powerful electrical storm rages on Saturn with lightning bolts 10,000 times more powerful than those found on Earth, the Cassini spacecraft continues its five-month watch over the dramatic events. Scientists with NASA's Cassini-Huygens mission have been tracking the visibly bright, lightning-generating storm--the longest continually observed electrical storm ever monitored by Cassini. Saturn's electrical storms resemble terrestrial thunderstorms, but on a much larger scale. Storms on Saturn have diameters of several thousand kilometers (thousands of miles), and radio signals produced by their lightning are thousands of times more powerful than those produced by terrestrial thunderstorms. The latest release (images) show an electrical storm 10,000 brighter than electrical storms on Earth. I would like to know how these storms are generated, i wounder do the Cassini scientist, have an understanding about these electrical storms work on Saturn.

matthewota      

04-27-2008   21:35:02

Incredible image as Cassini arcs into a high inclination orbit...it is a work of art as well as science.

3488      

04-27-2008   11:32:06

Very nice image of Dione. Even in Saturn-shine on the night side on the large ice covered moon, a wide range of surface features are visible, displaying a dynamic past on Dione, one of the most interesting of Saturn's moons. The overexposed day side will be ideal to search for possible geysers on the limb, a long shot I know, but worth a try. Andrew Brown.