After all the excitement of this photo of Saturn, here is another.  Well, not a photo.  It’s more like a CAT scan.  Once again it is the work of Cassini.

This false-color image of Saturn’s main rings was made by combining data from multiple star occultations using the Cassini ultraviolet imaging spectrograph.

During occultations, scientists observe the brightness of a star as the rings pass in front of the star. This provides a measurement of the amount of ring material between the spacecraft and the star.

Cassini has given scientists the most detailed view yet of Saturn’s densely packed B ring. Cassini found that this part of the rings is densely packed with clumps, called self-gravity wakes, separated by nearly empty gaps. These clumps in Saturn’s B ring are neatly organized and constantly colliding, which surprised scientists.

The clumps in Saturn’s B ring, 30 to 50 meters (100 to 160 feet) across, are too small to be seen directly. However, scientists can map the distribution, shape and orientation of the clumps. Colors in this image indicate the orientation of clumps, and brightness indicates the density of ring particles. The formation of wakes is strongest in the bluer regions, where ring particles clump together in tilted wakes. Particles in the central yellow regions are too densely packed for any starlight to pass through.

The ultraviolet imaging spectrograph measured the flickering of the star Alpha Arae as it passed by the rings Nov. 9 and 10, 2006.

This circumstance seems to me yet one more example among many previous thousands and many more thousands to come, of the fact that the true heroes of astronomy are the instrument makers.  The theorists theorise away, on the basis of insufficient evidence.  And they are eventually proved right, or then again wrong, by the next lot of instruments.  Once the instrument guys produce their next lot of pictures, the truth is pretty much clear for all to see, and frankly the theorists might just as well not have bothered.

As it says in the press release:

“The rings are different from the picture we had in our minds. We originally thought we would see a uniform cloud of particles. Instead we find that the particles are clumped together with empty spaces in between,” said Larry Esposito, principal investigator for the Cassini ultraviolet imaging spectrograph at the University of Colorado, Boulder. “If you were flying under Saturn’s rings in an airplane, you would see these flashes of sunlight come through the gaps, followed by dark and so forth. This is different from flying under a uniform cloud of particles.”

Because previous interpretations assumed the ring particles were distributed uniformly, scientists underestimated the total mass of Saturn’s rings. The mass may actually be two or more times previous estimates.

Previous interpretations?  Just extrapolations beyond what they had learned for sure from earlier instruments.  Guesses by people who didn’t know, in other words.  And then, thanks to Cassini, they did know.  And now they will make more guesses based on what even Cassini isn’t now telling them, which will be equally worthless, even if these guesses happen to be true.  Am I missing something?

I still don’t know how proper CAT scans work, or even, really, what they are.  But I am now confused about this on a somewhat bigger scale and in greater detail.