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Cassini Finds Source of Icy Jets On Enceladus
Not long ago, we discussed Cassini's mission to "skeet-shoot" Saturn's moon Enceladus in order to take high-resolution pictures as close to the surface as possible. Well, NASA scientists found what they were looking for. A newly released mosaic shows 300-meter-deep fractures in Enceladus' surface which are the source of enormous icy plumes that periodically erupt into space, reaching hundreds of kilometers from the moon's surface. Another picture shows one of the fractures in closer detail.
One revolution makes something 30 miles away appear to move 30*2*pi miles.
Rotation period = 30*2*pi miles / 15 miles per second = 12.5 sec.
Try to erase your mental image of something spinning rapidly.
"False color" images, when not used to impress technically illiterate folks, are used to highlight information that would otherwise be difficult or impossible to discern. In TFA, researchers colored the smaller bits of 'snow' that would not be visible in the image at the viewed resolution. That helps discern a trend instantly that, I'm sure, took the researchers quite a bit more time to figure out.
Usually, they're just for looks. Like Paris Hilton.
Faster! Faster! Faster would be better!
I assume by 'color spectrum' you are referring to visible light which our eyes are sensitive to and so allows us to see an image. The frequencies of electromagnetic radiation that are outside of this range can provide details that 'color' alone can't such as infra-red being able to penetrate dust that otherwise obscures the subject. Think of the impressive images of the Horsehead Nebula that were taken in infra-red as the Horsehead is believed to a dense cloud of tiny interstellar grains of dust that blocks the light of the emission nebula IC 434 and stars behind. While dark nebula are generally invisible (except of course where back lit as in the case of the Horsehead), their dust grains very effectively absorb light and ultraviolet radiation and then re-radiate this energy at infrared wavelengths.
For example here is a picture of a plume from Enceladus that was colorized for emphasis:
http://saturn.jpl.nasa.gov/multimedia/images/image-details.cfm?imageID=1874
But more specific examples for your question are these images:
http://www.nasa.gov/mission_pages/cassini/multimedia/pia06139.html
From the caption: "Red and green colors represent infrared wavelengths and show areas where atmospheric methane absorbs light."
http://chandra.harvard.edu/press/00_releases/press_030100a2142.html
In this case a picture in the X-ray spectrum allows them to see the temperature of the gas surrounding two colliding galaxy clusters; 50 to 100 million degrees C!
With a spacecraft the size of a bus, that's very fast. Especially considering that it takes tens of minutes to turn between targets, typically.
Just because you know things that can spin in less than 10 seconds doesn't mean that that's a reasonable rotation rate for every object.