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Saturn's Rings to Disappear Tonight
August 11, 2009 12:17 PM   Subscribe

August 11th marks the coming of Spring to Saturn's northern hemisphere, when the 170,000 miles wide rings turn edge-on to the sun and reflect almost no sunlight. The rings are only some 10 meters (30 feet) thick and made of mud and ice. As Saturn shifts towards its once every 15 year equinox, out-of-plane structures will cast long shadows across the rings' broad expanse, making them easy to detect (previously). Though you can't see the rings with the unaided eye, professional and amateur astronomers have captured the gas giant in its transition towards the equinox.
posted by filthy light thief (28 comments total) 10 users marked this as a favorite

 
If you're not sure where to look, Saturn is now only about 10 degrees above the western horizon an hour after sunset. In New Zealand, Saturn will be visible early evening only. Southern Sky Watch notes more astronomy dates for the coming months.
posted by filthy light thief at 12:17 PM on August 11, 2009 [2 favorites]


Fantastic stuff.
posted by Shohn at 12:21 PM on August 11, 2009


Coolest planet evar.
posted by Thorzdad at 12:22 PM on August 11, 2009


Astounding photographs.
posted by Blazecock Pileon at 12:45 PM on August 11, 2009


Latest raw Cassini images of the rings
posted by lukemeister at 12:45 PM on August 11, 2009 [1 favorite]


NASA has to be the coolest use of money ever.
posted by odinsdream at 12:47 PM on August 11, 2009 [4 favorites]


That's it, I'm dragging out my telescope tonight.
posted by beowulf573 at 12:52 PM on August 11, 2009


It appears something plunged through the F-Ring recently and was captured by Cassini. Pretty cool stuff.
posted by IvoShandor at 1:04 PM on August 11, 2009


I love the Cassini space probe. Does anyone know if there is Cassini memorabilia available to buy anywhere? I'd love to sport a totally non-ironic "Drop it like it's Huygens" t-shirt.
posted by fuq at 1:10 PM on August 11, 2009


fuq,

You can find some by googling 'cassini shirt -oleg' or 'cassini poster' or whatever.
posted by lukemeister at 1:20 PM on August 11, 2009


For a long time, I've thought that it was remarkably unfair that I didn't have a way to get to Saturn and a craft/suit strong enough to enable me to explore whatever surfaces lie beneath its atmosphere.
posted by Burhanistan at 2:55 PM on August 11, 2009


Saturn's Mysterious Splattered Moon
posted by homunculus at 3:10 PM on August 11, 2009 [1 favorite]


Awesome links that lead to more awesome links. Thanks!
posted by futureisunwritten at 4:37 PM on August 11, 2009


For a long time, I've thought that it was remarkably unfair that I didn't have a way to get to Saturn and a craft/suit strong enough to enable me to explore whatever surfaces lie beneath its atmosphere.

Same here, same here. I've always wanted to see what's going on underneath Jupiter's clouds.
posted by Blazecock Pileon at 6:25 PM on August 11, 2009


Same here, same here. I've always wanted to see what's going on underneath Jupiter's clouds.
it rains diamonds. srsly.

i've been following the cassini probe since well before launch, and i gotta tell ya, i'm kind of disappointed by the equinox coverage...they've posted one interview with one scientist, and put out one press release, both pretty information-free. yeah, we get that low angles of light are going to make more features apparent, but what are these features? what's going to happen? are the spokes expected to reappear? how long are they going to be in the dark? will the twisted rings (the ones whose particles orbit in spirals) reverse their direction of spiralling? will this 'blur' them for any period of time? is there going to be a movie of the event posted? why would you schedule a titan flyby for the equinox instead of focusing on the rings? and etc. and etc. and etc. also, with the flyby, there's probably going to be a week-long gap in updates to the raw images page (there usually is) grr. arg. i want to see this... animated! Of course, the little moonlet sunk in the rings and the 3D structure of the f-ring wakes is pretty groovy...just, y'know...MORE!

Does anyone know if there is Cassini memorabilia available to buy anywhere? I'd love to sport a totally non-ironic "Drop it like it's Huygens" t-shirt.

you mean something like the kermit-green "cassini launch team" t-shirt i have, with a line drawing of the probe and lander on the back, that i picked up at a thrift store near JPL for a dollar? I really have no idea, but feel free to seethe with jealousy over mine. I'm wearing it right now.
posted by sexyrobot at 8:05 PM on August 11, 2009 [1 favorite]


I've never understood how the rings could be so uniform and why they could stay there for so long.
Don't orbits naturally deteriorate? What is the repellent force keeping them out there, so close to the planet?
posted by Balisong at 8:50 PM on August 11, 2009


I've never understood how the rings could be so uniform and why they could stay there for so long. Don't orbits naturally deteriorate?

I don't think they're seen as orbiting debris so much as something in Saturn's magnetic field and/or centrifugal force is ordering matter that has emanated or continues to emanate from its atmosphere.
posted by Burhanistan at 8:53 PM on August 11, 2009


Don't orbits naturally deteriorate? What is the repellent force keeping them out there, so close to the planet?

1) No. when you hear about orbits 'deteriorating', you're hearing about things in low earth orbit, like the space station, or the space shuttle, which usually orbits at ~200-300 miles up, well within the earth's upper atmosphere. the atmosphere imparts frictional drag on the spaceship, slowing it down, and causing it to move to a lower orbit, where the air is thicker...slowing it down even further. objects in high orbit (~10,000 miles from the earth) experience almost no atmospheric drag, and will stay up practically forever. (the innermost rings are thousands of miles above the atmosphere of saturn, remember, saturn (without rings) has a diameter nine times that of the earth)

2) There is no repellent force. It's gravity that keeps things in orbit in the first place, otherwise they would just fly off into space. orbits come about because of the balancing act of two motions: the motion of the particle (ring particles in this case) perpendicular to the planet, and the motion of the particle towards the planet, due to gravity. explanatory animations: here.
posted by sexyrobot at 9:28 PM on August 11, 2009


I don't think they're seen as orbiting debris so much as something in Saturn's magnetic field and/or centrifugal force is ordering matter that has emanated or continues to emanate from its atmosphere.

*pinches bridge of nose, sighs*
1) No, they are orbiting debris.
2) Anything around saturn is in saturn's magnetic field. (it's back end extends halfway to the orbit of uranus) so what? the force of the magnetic field is negligible compared to the gravity of saturn.
3) they do not emanate, have never emanated, nor do they continue to emanate from saturn's atmosphere. current theories hold that they were formed from the disruption of a moon ~300km in diameter, but they might also be leftovers from the formation of saturn. more here.
4) as far as forces "ordering matter" here, again, the culprit is gravity. the banding structure, and gaps in the rings are caused by 'resonances' with the moons of saturn. orbital period is tied directly to altitude from the planet, so if you are a ring particle orbiting at a height that has a period of 1 day, and theres a moon further out that has a period of 2 days, then you are in a 1:2 resonance. twice in every orbit, you will be lined up with that moon and its gravity will pull you out of your orbit...this is what clears the gaps in the rings (there are other resonances as well, 1:3, 2:5, 7:11, etc...its the combination of these that cause each moon to leave a 'thumbprint' in the structure of the rings...also there are like 60 moons...thats why the structure is so complicated)
posted by sexyrobot at 9:49 PM on August 11, 2009


In the unlikely event that you don't want to seethe with jealousy of sexyrobot for the rest of your life, you can order Cassini swag from JPL. It'll cost more than a dollar, though.
posted by lukemeister at 9:57 PM on August 11, 2009


The equinox images are still coming down, so it will be a few days before there's a press release.
posted by lukemeister at 10:00 PM on August 11, 2009


you can order Cassini swag from JPL...

yeah my tshirts better. ;) but that floaty pen sure looks nice...mmmm, floaty pen.

The equinox images are still coming down, so it will be a few days before there's a press release.

yeah, i know...i just want it faster. why is the speed of light so. fucking. slow.?
posted by sexyrobot at 10:37 PM on August 11, 2009


I did some quick (and probably hopelessly wrong) calculations, and by my figures, if you wish to include Alpha Centauri in your diagram, you will need a monitor roughly 5000 miles wide. That is assuming the Earth -> Moon distance is about three inches on your screen (as it is on mine).
posted by Mitrovarr at 12:17 AM on August 12, 2009


Beautiful. Thanks for posting. If there's any justice, the funding to extend Cassini's mission until 2017 will be approved.

Also:
MetaFilter: its back end extends halfway to the orbit of uranus
(Was everyone being tasteful or something?)
posted by Pallas Athena at 6:11 AM on August 12, 2009


Yes, I hit post before I researched. Silly me.
posted by Burhanistan at 6:48 AM on August 12, 2009


Sawtooth Shadows on Saturn's rings. Not brand new, but recent.
posted by filthy light thief at 9:27 AM on August 12, 2009


filthy light thief that is definitely the best one so far.
posted by bukvich at 3:41 PM on August 12, 2009


From lukemeister's link to the Latest raw Cassini images of the rings: disappearing rings, translucent rings, shadowed Saturn(?), and other images that I can't comprehend.

I agree with odinsdream: NASA is worth the money, in ways I don't yet understand.
posted by filthy light thief at 2:13 PM on August 13, 2009


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