NASAs Cassini spacecraft has delivered a glorious view of Saturn... | Hacker News Reader

NASAs Cassini spacecraft has delivered a glorious view of Saturn...

nasa.gov

221 pointsjug6ernaut33 comments

Here's a fantastic detailed explanation of the geometry and what's going on with each visual element of the picture, from Slate:

http://mobile.slate.com/blogs/bad_astronomy/2012/12/20/satur...

Many thanks. I also like the 2006 picture mentioned at the end of that article - pics at http://www.ciclops.org/view.php?id=2230&js=1 . According to comments there, it seems that one won the BadAstronomy blog best pic of 2006 choice.

Quote: "Interior to the G ring and above the brighter main rings is the pale blue dot of Earth. Cassini views its point of origin from over a billion kilometers (and close to a billion miles) away in the icy depths of the outer solar system."

(Saturn is "icy depths of the outer solar system"? Well, I'll never! That's the Oort cloud. This is merely the better neighborhood, with the fancy planets ...)

Thanks for posting the article. Really helped!

If you're still having trouble wrapping your mind around the shadowy part... Look at this image and imagine the light source coming from behind instead:

http://upload.wikimedia.org/wikipedia/commons/0/0e/Saturn_HS...

Why do they look almost computer generated? Just curious.

If anyone stumbles upon a higher resolution image of this I would be much obliged. It's really striking.

edit: Just found it! http://i.imgur.com/ZCEKA.jpg

Just wondering, is there a network of telescope webcams? Hobby astronomers hooking up their telescopes to the internet, perhaps even with remote controlled mounts? Would save the costs of buying my own telescope, which wouldn't be much use in the city anyway.

You mean something like http://www.itelescope.net/ ? Also check for a local amateur astronomy association.

Research telescopes often have live feeds for popular events (such as the Venus transit).

Finally depending on your location you may be no further than a day trip away to an astronomical facility - they often have events open to the public, stargazing etc.

BTW Here's another "christmassy" picture (this time of the Bubble Nebula) from a brand new instrument:

http://www.noao.edu/image_gallery/html/im1136.html

Disclaimer - Latter link is my employer, but I have nothing to gain from you clicking on it :-)

Oh Edit: you can also go data-mining in public astronomy databases, though sadly most of them are not geared for use by the general public.

Oh Edit2: You can have some fun with this http://www.worldwidetelescope.org/ but you need Silverlight

Also this lot: http://www.lightbuckets.com/

Another related development in democratization of astronomy is publishing of transient events (brightenings/dimmings of objects) as they happen. You can subscribe to feeds from robotic transient surveys, that do the image processing and photometry to generate events in near real time (e.g.: http://skyalert.org/). The events are published in a standard format so you can automate follow-up as well.

Many of the events are asteroids or possible NEOs, but others are galactic and extra-galactic, like supernovae, blazars, etc.

It's not backyard astronomy, because the events are being detected by 1 meter telescopes and have magnitude of perhaps 18 or 20, but it's a more open and data-rich situation than a few sources being kept under wraps for follow-up by the discoverer only.

While I do find this image visually appealing, and appreciate its technical merit, I find it a bit unreal looking. Maybe it's a bit two-dimensional.

I prefer the more three-dimensional looking images like http://www.nasa.gov/mission_pages/cassini/multimedia/pia1462....

Well, it's the night side, so obviously there's not the same kind of shading that you get with direct sunlight.

The planet and the rings seem to violate 3D spatial relations. ie, planet appears outside the orbit of the rings, for example. Its a touch awkward. On a more subjective note, the outline of the planet in artificial colour (the corona effect) seems a bit ?? overdone.

I'd like to see other renderings.

edit: I think there is a bit of an optical illusion, part of which is happening because of the over-saturation of the corona. The image makes more sense if you soom out a bit and understand you are looking <up> at the planet from the souther hemispher (ie, below the equator/rings belt). The missing rings should be in the fore-ground but are absent due to shadow. Again, the corona;s colour saturation is so strong it throws the image constuct off when looking at it in more magnification.

I agree, but this helped. http://news.ycombinator.com/item?id=4952908

I can better appreciate the view now.

Yes; you're looking "up" but surely there are no missing rings - they are actually visible against the planet as silhouettes. They are dark because they're in the planet's shadow.

Polar vortex

http://www.nasa.gov/mission_pages/cassini/multimedia/N001983...

Saturn's polar vortex has a hexagonal pattern, which I think is pretty interesting: http://en.wikipedia.org/wiki/Saturn%27s_hexagon

Why does Saturn appear green in this image but brown in the banner image above it?

"The new processed mosaic [is] composed of 60 images taken in the violet, visible and near infrared part of the spectrum". So the colors in the image were chosen for artistic effect, and are not "true" colors because you couldn't see some of them anyway.

This image was specifically processed to look closer to real colors: http://www.nasa.gov/mission_pages/cassini/multimedia/gallery...

It left me wondering: could smaller rocky planets have rings or would their gravity pull not be enough to maintain them?

It is theorized that earth at one time had rings, but that they later coalesced into what is now our moon.

It is also theorized that the reason that the reason why Saturn's rings do not do this(though this could just a matter of time that we are now viewing them at) is because they are prodomonantly ice crystals which constantly bounce into each other breaking and re-freezing. IE why we can see them at all(reflective surfaces on the ice) rather then them be covered with dirt & dust and rendering them unreflective.

Further more to your question I "think" any planet or even any object could have rings, its just there are many factors that go into play and singularly it is REALLY hard to see them, and we only have our galaxy where we would be able to tell if an object did or didn't have them.

"It is theorized that earth at one time had rings, but that they later coalesced into what is now our moon."

Indeed. (1997 Nature article) http://www.nature.com/nature/journal/v389/n6649/full/389353a...

Also, almost by definition the rocky planets are the small inner ones. If they had rings and there was also a gas giant, the gravity perturbations from the giant would probably disrupt the rings fairly quickly.

[Probably too late, but for anyone reading this later.]

Oh we have a ring, its just full of telecommunication satellites :-)

... or of space debris. :-)

Must be an awesome view from the surface at midnight on Saturn.

Wow. Thank you for posting this. In light of the superstition of the day and recent events, I am reminded of Bill Hicks: http://www.youtube.com/watch?v=iMUiwTubYu0

That really is gorgeous. I want to be able to fly by it in person.

Is there a higher resolution image available? I'd love to make that a new desktop background.

The emperor's gorgeous new clothes.

Why does it look like clipart?

Because it is.

Because it's an exceptionally smooth and beautiful image?

Fake.

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