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NASA Discovers Giant Ring Around Saturn
caffiend666 writes with news that scientists using the Spitzer Space Telescope have discovered a very large, previously unknown ring around the planet Saturn. According to NASA, if the ring were visible to the naked eye from Earth, it would cover a patch of sky roughly twice the angular diameter of the Moon.
"The new belt lies at the far reaches of the Saturnian system, with an orbit tilted 27 degrees from the main ring plane. The bulk of its material starts about six million kilometers away from the planet and extends outward roughly another 12 million kilometers. One of Saturn's farthest moons, Phoebe, circles within the newfound ring, and is likely the source of its material. Saturn's newest halo is thick, too — its vertical height is about 20 times the diameter of the planet. It would take about one billion Earths stacked together to fill the ring. ... The ring itself is tenuous, made up of a thin array of ice and dust particles. Spitzer's infrared eyes were able to spot the glow of the band's cool dust. The telescope, launched in 2003, is currently 107 million kilometers from Earth in orbit around the sun."
Couldn't help myself, from TFA (emphasis added):
Before the discovery Saturn was known to have seven main rings named A through E and several faint unnamed rings.
What kind of a messed up numeral system do they use in NASA?
Joking aside, the ring divisions are labelled (from the closest to furthest) : D, C, B, A then F, G and finally E as the outermost ring.
Wonder what they will name this one, anyone good with sequence puzzles?
It's a very faint ring, more like a thin cloud. Voyager was generally not designed to study something that thin, unless perhaps they knew specifically what to look for, such as a specific wavelength. Plus, when you are "in" it, it's hard to have something to compare to know that there's a difference. You cannot rule out instrument contamination or noise when it's almost equal in all directions.
Table-ized A.I.
As others have pointed out, the issue was with luminosity, not being too small to see.
In fact, these rings are SO big that being close probably makes them even harder to see.
Consider that we know exactly what the shape of the Andromeda galaxy is, but we only have a general knowledge of the shape of our own galaxy. Or, consider that a person in a hedge maze might need an hour or two to accurately map it, but somebody flying overhead would just have to snap a photo.
On the topic of Andromeda - that galaxy is actually similar to the size of the moon in the sky (maybe bigger). However, it is too dim to see with the naked eye (maybe just a splotch in a very dark sky). A simple camera can get a decent shot of it given a long enough exposure time.
It is astonishing how little we know about the non-radiating matter in our own solar system. For example, the size of the Oort cloud is not really known.
We can see active galactic nuclei up to z=6.4 or 5.4 Gpc, but don't know the objects within 0.04 parsecs of earth yet.
The sphere is a beast.
NB: The message above might reflect my opinion right now, but not necessarily tomorrow or next year.
NASA posted a great composite shot a few years ago showing the full moon and the Andromeda galaxy at the same angular scale.
Astronomy Picture of the Day: Moon over Andromeda.