So you got a telescope for Christmas/Hanukkah/Newtonmass/whatever… or you’ve had one for awhile. Either way, you get a treat this week. Or a lack of one. Saturn’s rings are going away.
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| Hubble caught Saturn with edge-on rings in 1996. Image courtesy Erich Karkoschka (University of Arizona Lunar & Planetary Lab) and NASA/ESA. |
Well, kinda. Saturn, like the Earth, is tipped a bit compared to the plane of its orbit; we’re canted at a 23.5 degree tilt, and Saturn is off from being vertical by about 26.7 degrees. Saturn’s magnificent rings are aligned with its equator, so that means that roughly twice every Saturn orbit we cross the "ring plane". In other words, from Earth we see them edge-on.
And the rings are thin. Incredibly thin. Despite being over 200,000 km across, the rings are typically at most only a few dozen meters thick. To scale, that’s far thinner than a piece of paper.
So when we pass through the plane of the rings, they practically disappear from sight. I’ve seen it once through a telescope, when we were near (but not quite at) that point, and Saturn looks pretty weird when it goes commando. We’re used to it wearing these big gaudy rings, and there it was, nearly nude. It’s maybe not the best time to show the planet off to friends and family, but it’s still pretty cool.
The Earth actually doesn’t pass through the ring plane until September 2009, but at that time Saturn will be on the other side of the Sun, and pretty much unobservable. You’d think that a month or two before then would be the best time to observe the narrowly thinning rings, but in fact the best time is right now! Due to the vagaries of our mutual orbits, the rings are actually at a minimum right now, the last week of 2008, when they are inclined just 0.8 degrees to our line of sight.
If you have a telescope, get out and take a look! Saturn will be nearly ringless for the next few months, and then the rings will start to open up once again. After that, you’ll have plenty of time to soak in the phenomenal view of the solar system’s best showpiece — the next ring plane crossing isn’t until March of 2025.
Right now, Saturn is in the constellation Leo and shines fairly brightly at about magnitude 1, about the same brightness as the star Regulus which marks the heart of the lion. It rises around midnight local time right now, and is high enough to observe a couple of hours later. You can find sky maps at Your Sky and Heavens Above, and you can read more about the ring plane crossing on the NASA news page, and on Alan Dyer’s astronomy page.
And I have to add: this isn’t merely a curiosity; there is scientific value to this event. Telescopes can focus on the planet and see things otherwise hidden in the glare of the very bright rings. Faint moons, the existence of material above and below the ring plane, features on Saturn itself: all these can be easier to see without the icy, reflective ring particles blasting out light. It’s funny. Saturn is the most beautiful planet in the solar system through a telescope because of those rings, but it may be the most scientifically interesting when we can’t see them at all.
December 25th, 2008 at 11:51 pm
Well, this certainly makes me want to buy another telescope!
December 26th, 2008 at 12:31 am
I’m reluctant to stay out past midnight to observe, but considering this won’t happen again until 2025, perhaps I should. Hopefully the clouds won’t conspire to ruin the night. It’s not until I purchased a telescope that I really took notice of how often the skies are cloudy where I live. Well… either that, or weather patterns are caused by telescopes being pointed at the skies.
December 26th, 2008 at 1:58 am
You don’t need to stay up after midnight to see Saturn. Just get up before dawn, which isn’t that hard at this time of year.
December 26th, 2008 at 3:08 am
Neato. If I actually owned a functioning telescope, I would certainly stay out to observe.
Also,
“Despite being over 200,000 km across, the rings are typically at most only a few dozen meters thick. To scale, that’s far thinner than a piece of paper.”
It is?
December 26th, 2008 at 4:32 am
It’s unfortunate i did not treat myself with a pair of binoculars or even a scope for christmas. Also unfortunate upon moving to my new home I misplaced my binoculars.
Hopefully I can get myself a scope or even binoculars for this period of time. I hope to witness this awe inspiring view the solar system is presenting to the cosmos.
December 26th, 2008 at 5:01 am
Hey, the weather is going to be fine the next days (cloudless and cold). I think I will take that chance. Thanks a lot for the information!
Btw: There was something very strange yesterday. It was about 7pm CentralEuropeanTime (GMT+1). I was watching out of my window seeing the (extreamly) bright Venus and just a little east to it there was a bright flash rapidly fading. I haven’t seen any movements so didn’t made any wishes (
) but since I haven’t heard anything yet, I don’t think it was a Supernova which would’ve been totally cool! Luck wasn’t with me I bet. I still don’t know what it was, but it could have been anything
December 26th, 2008 at 6:03 am
While you’ve got the telescope out, we are also in a season of mutual events of both Jupiter’s and Saturn’s moons – when they eclipse and occult each other. See http://www.imcce.fr/fr/presentation/equipes/GAP/travaux/phemu09/index_en.html
December 26th, 2008 at 6:23 am
Thus Kronos swallows his children.
(Isaac Asimov – ‘The planet that wasn’t’ http://geobeck.tripod.com/frontier/planet.htm )
December 26th, 2008 at 6:56 am
I hope I get a chance to check this out…I’ve been clouded out for weeks.
I just got some new eyepieces for Xmas too!
December 26th, 2008 at 7:49 am
“Due to the vagaries of our mutual orbits, the rings are actually at a minimum right now, the last week of 2008, when they are inclined just 0.8 degrees to our line of sight.”
Just out of curiosity… what are those “vagaries?” Or at least some of them. I’m not sure I understand why the rings would appear more edge on nine months before we cross their plane than closer to the time of the crossing… or did I misinterpret something in there?
December 26th, 2008 at 8:19 am
As a kid I found the disappearance of Saturn’s rings to be incredibly depressing. I mean, c’mon! It’s Saturn!
I do remember one night with the high school science club, trying to convince our advisor that it was indeed Saturn I was showing everyone. “It’s Jupiter!” “No, it’s Saturn…the rings are edge-on.” “It’s Jupiter!” I then proceeded to point the telescope at Jupiter. Oh, I was a vindictive little bitch, even then.
December 26th, 2008 at 8:24 am
Thus Kronos swallows his children.
(Isaac Asimov – The planet that wasn’t)
December 26th, 2008 at 8:51 am
As an aside, I’ve been wondering recently how much processing power it would take to simulate a planet wide laboratory, in which the primordial atmosphere(likely very similar to that of Saturn, though with much less H2 and He), follows the known rules of recombination of various elements required for life. A simulation which could emulate the real world biochemistry at approximately 100 million times faster than real time, might point the way to (the mechanism of)spontaneous generation of life???
If the simulation ran long enough AND electronic “life”(defined as a self sustaining/self replicating data pattern) made its appearance, that might actually go a ways to defusing creationists resistance to life not requiring intelligent influence in order to get its start,,,
,,,maybe a few hundred thousand PCs running together online could do that trick,,,
Hey, I’d volunteer my iMac for that.
Gary 7
PS,,,must,,, point ,,,8 inch ‘scope,,,in right direction,,,upward!!!
December 26th, 2008 at 9:01 am
@ Elwood:
And Galileo before Asimov!
December 26th, 2008 at 9:03 am
@ Gary:
As an aside, I’ve been wondering recently how much processing power it would take to simulate a planet wide laboratory
Hm… maybe something run by little white mice? I can save you a lot of trouble: the answer is 42.
December 26th, 2008 at 9:27 am
So, this time of year known as ‘the holidays’ – you can definitely with someone a Joyous Saturnalia?
J/P=?
December 26th, 2008 at 9:28 am
with=wish
(what the heck, it’s raining, I was laid off work, etc….)
J/P=?
December 26th, 2008 at 9:36 am
Laid off on Saturnalia? Oh, man, John, that’s harsh.
Hope you have a better new year.
December 26th, 2008 at 9:40 am
Saturn’s rings are going away.
I wondered when someone was going to clean up that mess.
December 26th, 2008 at 9:52 am
kuhnigget: exactly – that was the point of Asimov’s article.
I posted a link but it’s awaiting moderation
December 26th, 2008 at 10:05 am
@ Elwood:
I figured…just couldn’t help being snarky.
December 26th, 2008 at 10:52 am
Katherine: A sheet of paper is roughly 20 x 27 centimeters (call it 20). A stack of 500 of them is roughly 5 cm thick. So each sheet is about 5cm/500 sheets = 0.01 cm/sheet. That’s a thickness to width ratio of 0.01 / 20 = 0.0005.
Saturn’s rings have a thickness / width ratio of about 100 meters / 200,000,000 meters = 0.0000005.
So to scale, paper is far, far thicker than Saturn’s rings. 1000x thicker!
December 26th, 2008 at 11:30 am
Great, now Saturn is going to go Photoshop it’s rings so they look bigger, then Saturn’s ad goes up on Craigslist. Thanks a lot, Phil, like Saturn wasn’t already insecure enough.
December 26th, 2008 at 11:43 am
Yeah, I’m with Katherine about “to scale” not coming across in the way you probably meant it. For example, if I have a sheet of A4 size office paper and you have the same kind of paper in letter size, your sheet is thinner to scale than mine.
And in your explanation, the thickness went from “at most only a few dozen meters” to 100 meters while the units for “across” changed from meters to kilometers. Seems like maybe a problem of magnitude, but not quite.
Also, I’m not campaigning to have December 26th designated as “Pick on an Astronomer” day on the Internet, but using “across” to describe circles usually means diameter while if you’re describing a ring you might want to make it clear if “across” means the width of the ring belt (outside to inside of any section) or the width of the entire system (outside to outside, including Saturn itself).
Here’s what would make the thickness of these rings clearer to me – and I’m a math disaster at the moment or I’d figure it on my own:
If Saturn and its rings were scaled so Saturn was the size of the Earth, would the outer rings reach our moon, or pass it? Would the inner rings hover in the general neighborhood of our geosynchronous satellites? Would the rings be as thin as paper? (And if we had similar rings here, how much shadow might they cast on the first day of summer or winter?)
December 26th, 2008 at 11:54 am
I wish that I had a telescope. Still, that is totally awesome.
December 26th, 2008 at 12:15 pm
For those of us under continuous cloudy skies you can go to Alan Dyers astronomy site (linked in Phil’s article above), click on Alan’s picture of the Saturn’s oppositions 2001-2029, and then view it as you would a magic eye picture. If you know how to do that you’ll see several images of Saturn in glorious sharp 3D….good enough for me at least till the skies clear.
December 26th, 2008 at 2:02 pm
I don’t have a telescope yet but my parents gave me a check specifically for my telescope fund. Going to get one early next year. Won’t be big or fancy but worlds better than my rather poor eyesight.
Saturn is one of those things I really look forward to take my first view of through a telescope along with Jupiter and Mars.
December 26th, 2008 at 2:15 pm
Will I be able to see the rings if I stoop down or stand on my tippy toes?
December 26th, 2008 at 3:21 pm
I’m with DaveS and Katherine here. The whole time I was reading the remainder of the post, I was thinking, “What scale? 1:1 ? That would make them ‘dozens of meters thick…’ Or it could be a scale of 1:2 in which case they’d be half dozens of meters thick. Still too thick for paper. Hmm…”
December 26th, 2008 at 5:53 pm
We have this very photo in a large size with a big mat on the mantel in our living room. In another room is a large M31 photo.
December 26th, 2008 at 6:49 pm
I’m with the pedants:
Saying something is thinner than a piece of paper is about as useful as saying something is as long as a piece of string!
December 26th, 2008 at 7:10 pm
if i evr gets 2 b Ceiling Cat, i wil bees in ur soler sistum, makin ur Urfs wif teh ringz. cuz deys TEH AWSUM like Ceiling Cat. =^..^=
December 26th, 2008 at 8:39 pm
Phil, please put some time back into writing the dissections and critiques of the “bad astronomy” that began your flirtations with internet fame. I’m already aware of Saturn’s current appearance, and there are plenty of well-written astronomy websites to inform those who want to know. Don’t just cater to the fark.com crowd so you can get lots of hits on your shiny new blog. You used to point out all of the BAD stuff that showed up in media reports of things like this. I’m sure you wouldn’t have to look very far to find a current article about Saturn that contains all sorts of errors and misinformation. I want to know what you think of the latest clap-trap that passes for science in the movies and the news. Where is your review of the new Keanu Reeves crapfest? I don’t bother to look at your site anymore unless FARK links to it, because I know these days you’re usually writing about some bit of space news that has already been reported elsewhere.
I dare say that your little blurb about sheets of paper and Saturn’s rings is just an attempt to cater to the unfinformed, a “misuse of science”, if you will.PLEASE.
/get back, JoJo
December 26th, 2008 at 9:15 pm
Daniel J. Andrews:
When I do that the inner ring looks curiously tubular … like a hula-hoop. I guess because those images are not intended for 3-d viewing.
December 26th, 2008 at 9:44 pm
Daniel J Andrews wrote:
The magic eye is working, but never in this fashion. How does this presentation of a series of images make me see five columns in 3D when it only contains four columns in 2D?
It’s wicked cool but I’m not understanding.
December 26th, 2008 at 9:50 pm
Sure it was a clumsy sentence (saying “to scale” before introducing the concept of comparing it to a piece of paper), but come on – you guys can figure out what the author meant.
I do wish he had given a precise number instead of a “few dozen meters”, which in my mind could mean anything from 24 to 100+. Heck, the Marines use the word “few” to describe 120,000 people.
December 26th, 2008 at 9:58 pm
Whoops! May have just figured it out.
Because adjacent images are similar to the view between two eyes. Adjacent images show a difference in time that is equivalent to a difference in perspective! The magic eye blends adjacent images similarly to how it blends red/blue images. Neat. Time and POV are the same (under strict conditions)!
And the universe is suitably embellished.
December 26th, 2008 at 10:36 pm
If I am wrong, I admit it.
In this case, I am not wrong. “To scale” has a specific meaning, and that is like a scale model. A piece of paper is colloquial enough to mean a single sheet of paper, and it doesn’t matter if it’s A4 or a piece a meter across; as I showed in my comment above, a piece of standard typing paper is, to scale, 1000 times thicker than the rings.
“Across”, similarly, has an obvious meaning as the diameter of the rings. And the rings are, to scale, so much thinner than paper that it doesn’t matter if I say they are a 10 meters thick or 100 meters thick. I was making very rough estimates, and because of that 100x scale factor precision isn’t necessary.
And Space Elevators, I debunk bad science on this blog all the time. Like, almost every day.
December 27th, 2008 at 2:09 am
Does anyone have any idea whether the rings are at a constant, stable thickness, or are they tending to consolodate toward a metre thick say, or possibly increasing in thickness? Have any measurements been done?
December 27th, 2008 at 2:30 am
Dictionary.com:
pedant noun 1. A person who makes an excessive or inappropriate display of learning. 2. A person who overemphasizes rules or minor details. 3. A person who adheres rigidly to book knowledge without regard to common sense. 4. Obsolete. A schoolmaster.
December 27th, 2008 at 5:49 am
So if we can’t ring Saturn does that mean we have to email or snail mail for this year now ..?
Sorry, couldn’t resist. Ducks & runs for cover ..
December 27th, 2008 at 6:10 am
kuhnigget Says: (December 26th, 2008 at 9:01 am)
“@ Elwood: And Galileo before Asimov!”
Actually Isaac Asimov was quoting Galileo in onbe of his non-fiction pieces – & yes Asimov cited him.
Asimov actually spent more time and effort on writing his “popular” science articles including a couple of books devoted to Astronomy than he did on his SF works.
A few examples – (in Harvard uni. style (?) cites with publisher & date in brackets after italicised title.)
1. his childrens series on the solar system :Isaac Asimov’s ‘Library of the Universe’
2.‘Asimov on Astronomy’ (Coronet Books, 1974.)
3. ‘The Tragedy of the Moon’ (Coronet books, 1973.)
4. ‘Planets for Man’ – with Stephen H.Dole based on a Rand study into extraterrestrial life incl. candidate stars. (Random House / Rand Corporation, 1964.)
5. ‘Alpha Centauri – the Nearest Star’ ,Lothrop, Lee & Shepherd, 1976.)
6. ‘Counting the Eons’, (Grafton Books, 1985.)
& sorry Phil but he even preceded you with includingastronomical natural hazards in his book :
7. ‘A Choice of Catastrophes’, Hutchinson, 1979-1980.)
… Plus teher alot more one sonastronomy and science more broadly that Asimov wrote too – those are just my personal seven faves!
There’re all still good reading too albeit a little dated in some cases.
Whoa that guy was prolific -and good! You’ve got at least another 500 odd books to write to catch up wth him, Dr Plait!
December 27th, 2008 at 6:53 am
Make that :
& sorry Phil but he even preceded you with including astronomical natural hazards in his book : …
Plus there’s a lot more ones on astronomy and science more broadly that Asimov wrote too – those are just my personal seven faves!
December 27th, 2008 at 7:01 am
@ NorthGuy‘s
“Will I be able to see the rings if I stoop down or stand on my tippy toes?”
Uh, I’ll assume you’re bein’ as silly as I am but the answer is _no_ sorry you can’t.
What you need to see them nice and big again is a time machine … Future or past? It don’t matta as long as it ain’t anotha ring-lane crossin’ .. What %-age of the time is that? Dunno but not often!
December 27th, 2008 at 8:06 am
@ Ivan:
4. Crank, one step removed from. See nutter.
December 29th, 2008 at 11:12 am
It is interesting that we are seeing Saturn’s rings edge on this year, while the Cassini spacecraft is in a high inclination orbit around Saturn at this time.
December 29th, 2008 at 4:27 pm
[...] Saturn Gets Edgy So you got a telescope for Christmas/Hanukkah/Newtonmass/whatever… or you’ve had one for awhile. Either way, you get a treat this week. Or a lack of one. Saturn’s rings are going away. [...]
December 31st, 2008 at 10:40 am
Speaking of vagaries, what kind of physics makes the rings that thin? To channel my inner six-year-old: “Why?”
January 4th, 2009 at 11:33 pm
I’ve had my telescope for about a week now, and I haven’t been able to find Saturn yet. I follow the star charts that I download, but I can’t seem to find it. I’ve had no problems with Venus and Jupiter, but pesky Saturn keeps on hiding from me.