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Saturn Rings But No Spokes
An anonymous reader writes "Scientists continue to ponder why images of Saturn's rings today lack the 'spokes' or dark radial bands radiating outward and first observed on the Voyager flyby. The Boulder-based Cassini Image Team describes 5 visible moons, plans for the descent probe going into the Titan moon's hydrocarbon-rich atmosphere and the expected orbital entry around Saturn less than 4 months from now."
If only NASA would bring the success of this mission into the public spotlight as a way to raise awareness as to its more successful programs.
That's absolutely true. After what happened with the Columbia, NASA really needs to boost public support for their programs. People see the 2 shuttle disasters that have occured as being the bulk of what they accomplished, and that is just wrong.
And of course, I'm not saying what happened isn't tragic. But people dont understand that many astronauts understand that disaster is a possibility, and they're willing to take that chance in the pursuit of the Greater Understanding.
NASA really has to get the PR machine in motion
Are you sure it would send the right message?
It sort of seems to me like saying "unmanned exploration is really successful, but look at how many people we killed with stupid manned exploration, that could have easily been done unmanned".
I've had enough abrasive sigs. Kittens are cute and fuzzy.
I'm sorry, maybe I'm just an idiot, but I don't really see any of the 'spokes' in the image you linked to.
Could somebody paste a big red arrow on there for the outer-space-cluefully-impared, such as myself?
Thanks.
There were no real current Astonomy Picture of the Day references so I linked to a search on Saturn. This gives quite a few different views of Saturn and some other related material as well.
Use your head, can't you, use your head,
You're on earth, there's no cure for that - S. Beckett
By the way, next summer NASA's Cassini spacecraft, launched in 1997, is scheduled to go into orbit around Saturn and its moons for about four years.
The piggybacking Huygens probe is scheduled to go into the hazy Titan atmosphere and land on the moon's surface (if all goes well). The Huygens probe is geared primarily towards sampling atmosphere. The probe is equipped to take measurements and record images for up to 30 minutes on the surface. But the probe has no legs, so when it sets down on Titan's surface its orientation will be random. And its landing may not be by a site bearing organics.
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Obviously the Fithp has already left Saturn and is headed to Earth.
Time to start studying those old Orion plans...
The "spokes" are odd disruptions in the rings caused by Saturn's magnetic field rotating through them. They show up as dark patches radiating directly away from Saturn or occasionally arching, and they travel like a wave around Saturn in time with its rotation. It was this timing/speed that tipped astronomers off as to what was causing them, incidentally.
So if the spokes aren't visible now, maybe Saturn's magnetic field is fluctuating/less coherent than normal. It's a gas giant so its field could be less stable than the denser planets. There may be some low-level eg mid-atmosphere storm disrupting the normal field-generating circulations.
Just a thought. IANAA
cheers, Sal
--
Sal
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Perhaps the spokes don't show up because they're not applying those same techniques? I certainly don't see any mention of those techniques in the article in the first link.
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This is an offtopic comment: offtopic because it was stolen verbatim from a totally unrelated story:
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http://science.slashdot.org/comments.pl?sid=793
It's just an excuse to get the
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have been seeing spokes in the rings for quite some time using ground-based telescopes of various sizes. This may be one of those features, like the canals on Mars, that shows up because the eye-brain software processes images differently than the spacecraft ccd-computer does. An article in Sky & Telescope discovered they could reproduce the canal effects using the techniques of registration (stacking), and various applications of wavelets and other processing methods. They concluded our eye-brain mechanism does something similiar in real time at the eyepiece during moments of steady seeing conditions, causing dark lines to be seen where a smoother color gradient actually exists.
The post is not exactly a troll and makes sense enough to be moderated as interesting. However, nobody wants to see some idiot gaining karma points by mooching off of some other persons opinions/ideas. Shouldnt there be some mechanism whereby the post is modded up but the poster does not get the mod points? Or at least some reporting interface that will blacklist the poster for having copied the post verbatim...
Note, if the poster had given due credit to the original post, it probably would have been okay.
Saturn rang? And no one spoke with it? Geez, maybe it woulda told us everything.
But isn't that the truth? Let's face it, manned exploration IS orders of magnitude more expensive than unmanned, doesn't provide much more benefit from a scientific viewpoint, as is infinitely more tragic when things go wrong. If we still want to do manned exploration because of the "cool factor", then so be it, but let's not lie to ourselves about the facts.
I don't care if it's 90,000 hectares. That lake was not my doing.
It sort of seems to me like saying "unmanned exploration is really successful, but look at how many people we killed with stupid manned exploration, that could have easily been done unmanned".
Well, that's exactly the message many of us would like to get out. Using astronauts is hot stuff for the evening news but otherwise is rarely of much value. Even the "rescue missions" for things like the Hubble probably don't break even. The development and maintenance cost of the shuttles, space suits, manned safety environment, etc., has gotta be more than sending up full replacement systems.
https://app.box.com/WitthoftResume Code: https://github.com/cellocgw
Maybe a decent sized object passed through the rings, disturbed them and left.
Either that or some stoned punk aliens were waving their hands in front of the Voyager cameras just to screw with us.
This is my sig.
In all the APOD picture of Saturn I found a reference to Spokes and a picture that contains them.
Use your head, can't you, use your head,
You're on earth, there's no cure for that - S. Beckett
Agreed.
I think that a well-trained geologist/astronaut could pull far more information from a short walk on mars than those rovers could their whole time on the surface. Besides being infinitely more maneuverable than any robot, living astronauts can devise new experiments and fix things when they go wrong. Anything a robot can do, an astronaut in a space suit can do BETTER by several orders of magnitude.
Now, when things go wrong, it is much less tragic to lose a robot than it is to lose a space crew. However, any crew embarking on such an expedition will be fully cognizant of the risks, and I am sure that even if the trip was a guaranteed one-way ticket to mars that qualified volunteers could still be found.
I was a young engineer at JPL when Voyager 2 encountered Saturn, and I remember when the first photos of the spokes in the rings were displayed in real time on the monitors in the cafeteria. The work on other projects had pretty much ground to a halt while everyone watched the data come in.
Of course, the real time data had no captions, no explanations of what we were seeing, so we had all sorts of guesses - density waves, camera artifact, etc. Once it was apparent that the waves were holding together as the rings rotated and were not being sheared apart, it was clear they were not due to any gravitational effect. Since they moved with the rotation of the planet, the accepted explanation is the magnetic field of Saturn causing the charged dust in the rings to concentrate into visible spokes. As I understand it, the spokes are not a wave phenomenon at all.
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I was wondering if the planetoid and particles could be doing the wave.
Generally these things are oblong rather than spherical. Maybe there is some gravitational coupling between the particle shape and Saturn and/or the other neighboring particles.
The particle could be spinning along their axes perpendiculr to the ring and along the line from the center of Saturn to the particle.
When the particles long axes are aligned perpendicular to the plane of the ring they would look one way (reflect less light perpendicular to the plane of the ring). Then when they rotate with the long axis in the plane of the ring they reflect more light perpendicular to the plane of the ring - they look brighter.
Admitttedly the dipole interaction would be pretty small. But this would allow for no spokes in the sense of ripples in the particle density but still allow us to "see" the spokes.
Anything a robot can do, an astronaut in a space suit can do BETTER by several orders of magnitude.
I doubt that.
First: No astronaut likes to take 10000 examples and analyses them 10000 times. A robot doesn't complain. A robot doesn't get tired. A human does.
Second: A robot can be build adapted to the martian surface: A third the weight for the same mass, no breathable air, sandy environment... For a human, you have to put lots of technology into the space suit to adapt to the martian environment, and the astronaut is occupied carrying it around instead of performing experiments. And working in a space suit is not as easy as just with a labor suit.
Third: A robot can have everything builtin needed to perform analysis. You can design everthing in a size fit to the experiment you are planning. For a man you have to have everthing in the size a human needs it to handle. A human may not be able to perform all experiments during the walk outside, she has to carry her martian examples into the space station and work in the lab, which takes much longer.
The only thing humans are better than robot is to react at unexpected situations. But since the experiments are already preplanned on earth and the space ship is designed for and loaded with the equipment for exactly those experiments, humans don't have much chance to adapt to unexpected situations. What unexpected situations anyway? Suddenly a martian jumping at people? Basicly there are two types of unexpected situations a human could be forced to react on: a) something dangerous happens. Then be glad you just loose a robot. b) there is a chance to analyse something you didn't expect to be there. Then the human doesn't have the equipment to analyse either (and because we don't send McGuyver, he can't built it out of martian dirt). And there is still the earth station, and most of the robots are reprogrammable and remotely guidable anyway, so you may be able to adapt the experiment to the new situation.
With the ESA Beagle we had a situation where a human being around may have helped. She could just take the beagle probe and turn it back on after it failed somehow. But it's much cheaper to just send a second beagle probe to Mars than to send and bring back a human being.
About 30 seconds after posting the above I found this link, to an abstract of a scientific paper detailing Hubble observations of the spokes.
NASA really has to get the PR machine in motion
Please add one key adjective to your request: "NASA really has to get the honest PR machine in motion". It's one thing to try to make science and exploration more interesting to non-science people. It's another to spin every news story so it becomes unbelievable.
(I don't have a tinfoil hat. Really.)
The only thing humans are better than robot is to react at unexpected situations.
[snip]
What unexpected situations anyway? Suddenly a martian jumping at people?
Good one, because, as we all know, nothing unexpected ever happens in space.
Let's see...
PROBLEM: Dust buildup on solar panels
Robot: Screwed because no way to clean it off.
Human: Wipes dust off
PROBLEM: Martian dirt is sticky. Is it because of brine, or is it anelectrostatic thing?
Robot: Takes a closeup picture. Can't tell definitively. Debate ongoing.
Human: Reaches down, touches dirt with glove, has a closer looks, problem solved in two seconds.
Aside: what's the latest story on that dust? I haven't bothered to read up since the last 'brine' hypotheses hit the news.
PROBLEM: Dirt has a crust on it, want to take a look what's under the dust.
Robot: Fixes five wheels in place, while spinning the sixth to break the crust.
Human: Takes a spade...
PROBLEM: Crater wall is steep, interesting deposits halfway down (let's presume here).
Robot: Takes a zoomed-in picture but cannot climb down.
Human: Climbs down, samples deposits, locates water.
The presumption that we could build a robot with the same data-gathering capabilities as a human equipped with an array of scientific equipment is absolutely preposterous, at least in this day and age.
No astronaut likes to take 10000 examples and analyses them 10000 times
No kidding, that's what robots are best suited for, at least right now. Presumably, if any such activity were planned, the astronaut would bring an auto-sampling machine of some sort with them.
Maybe in the future we'll build robots that can gather data as well as a human, but that future is still a ways off.
When will Cassini photograph the monolith on Iapetus.
"dammit, we forgot the spokes. Quick, get that guy that colours the martian sky blue to add some in to the new pictures".
"plans for the descent probe going into the Titan moon's hydrocarbon-rich atmosphere and the expected orbital entry around Saturn less than 4 months from now."
All Iraq-related kidding aside, I find this interesting. Saturn is too far out for modern solar energy solutions to be viable, we still haven't figured out the whole fusion thing and hydrogen doesn't like to be cracked out of water. On the other hand, hydrocarbons want to be broken down and we know all about harnessing the energy of that reaction and we'd have uses for the byproducts (soot may not be desirable here on earth but carbon is a pretty good radiation shield). We can do something with this once we get there.
Why are there spokes in the Voyager images but not from Cassini? Because Janeway was a nutcase and mismanaged just about every aspect of her mission!
Anyone who trusts Voyager's telemetry with her in command over even the comparatively primitive computer and sensors Cassini uses is an idiot!
I think that a well-trained geologist/astronaut could pull far more information from a short walk on mars than those rovers could their whole time on the surface.
But for the same price as one well-trained geologist/astronaut, you'd get a *hundred* rovers spread all over Mars. You must compare 1 with 100, not 1 with 1.
any crew embarking on such an expedition will be fully cognizant of the risks
Yeah, the same way those Shuttle crews were kept fully informed of aware of the risks by the NASA administration.
Dialectician. Archology.
Well, I think we have to ask ourselves about the real purpose of the space program. The fact is that space science has few useful applications on Earth (despite the spinoffs which NASA keeps bragging about), and if science were our only goal, we'd be better off spending the money on other projects. Heck, even fusion reactors and particle accelerators would give us more bang for the buck.
No, I think that the real reason to send people into space is so people can be in space. Earth is starting to get too small for us, and there's always the risk of some global disaster, so people should think about colonizing the solar system (and, eventually, other systems). And while sending robots to Mars may teach us a bit about Mars, what we really need to know is how humans could live on Mars, and the simplest way to figure that out is to send a human.
Oh yeah, and in response to your sig:
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Condorcet: A Better Election Method
All it takes is nukes and nerves.