Flows made visible

Galileo commands us “Measure what can be measured, and make measurable what cannot be measured.” An updated version of this might be “Visualize what can be visualized, and make visible what cannot be seen.”

If you grew up with a globe like this, you can be forgiven for thinking the big blue oceans weren’t much more than big and blue. But even a sailor with direct experience of the sea and its many tides and currents might be surprised by what the folks at NASA have done with a visualization called Perpetual Ocean.

Maximize the window when you look at it. There’s so much to see. The Gulf Stream jumps out, as you would expect. But what about the string of gyres peeling off South Africa? You can see how shallow and relatively calm the Java Sea and Strait of Malacca are, whereas the Caribbean fairly churns. And then there are the spectacular Roaring Forties that chase their own tail all the way around Antarctica. So much to see.

It’s one thing to be shown something new that you’ve never considered, something like the surface of Titan or a giant aquatic isopod. But to suddenly see something that is all around you, to have the mundane made exotic, that can be something of a shock. It’s also worth considering that, as complex as these flow diagrams are, they still constitute only one two-dimensional slice through a larger and still more complex three-dimensional flow field. I guess visualizing that that can wait a few years.

Flow visualizations seem to be in the air these days (heh), because what NASA has done with water, Martin Wattenberg has done with air. Behold his Wind Map. Where does all that wind come from? And where does it go to? A visualization can only tell you so much. Someone older than Galileo had words on the subject: “The wind bloweth where it listeth, and thou hearest the sound thereof, but canst not tell whence it cometh, and whither it goeth.”

While I was watching all these visualizations, I was thinking to myself, where have I seen that before? Then I remembered this little guy that made the rounds a few months ago.

Like I said, flow visualization is in the air. And the water and the stars, I suppose.

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