September 8: Alternate-universe nostalgia

I'm not entirely sure what this photo means (though I don't think it's good), I just find it hypnotic

In my head I dislike nostalgia, because I'm convinced, intellectually, that we should be looking forward into an ever more-glorious future. Otherwise, what's the point of not drinking in the mornings? But often I'm a sucker for its narcotic charms (although I'm doing pretty good at resisting drinking till lunch.)

Today's reading from one of the Science! volumes, Helmholtz on glaciers, manages to evoke two kinds of noncanonical nostalgia -- one for a world I never knew, the other for a world that's still existing, barely.

"The world I never knew" nostalgia comes from the nature of this volume, which consists almost entirely of public lectures. Public lectures! Entertainment for the radio-less! I guess we have the same thing now with TED talks and such, but the idea of gaining knowledge as something to do with your evenings; well, it's hard for the nerd not to feel wistful.

And the other nostalgia, the pre-emptive kind, comes from the fact that its about glaciers, which, of course, we seem to be doing our best to get rid of, because who needs fresh water? Without getting too much into the post, it does remind you of how our planet is an extremely delicate, almost accidental, system:
To this must be added another property of air which acts in the same direction. In a mass of air which expands, part of its store of heat disappears; it becomes cooler, if it cannot acquire fresh heat from without. Conversely, by renewed compression of the air, the same quantity of heat is reproduced which had disappeared during expansion. Thus, if for instance, south winds drive the warm air of the Mediterranean towards the north, and compel it to ascend along the great mountain wall of the Alps, where the air, in consequence of the diminished pressure, expands by about half its volume, it thereby becomes very greatly cooled—for a mean height of 11,000 feet, by from 18° to 30° C., according as it is moist or dry—and it thereby deposits the greater part of its moisture as rain or snow.

And, of course, this, which if it weren't about heat would be chilling:
Our atmosphere is like a warm covering spread over the earth; it is well-nigh entirely transparent for the luminous darting rays of the sun, and allows them to pass almost without appreciable change. But it is not equally penetrable by obscure heat rays, which, proceeding from heated terrestrial bodies, struggle to diffuse themselves into space. These are absorbed by atmospheric air, especially when it is moist; the mass of air is itself heated thereby, and only radiates slowly into space the heat which has been gained.
Hmm. Maybe that morning Scotch is starting to look good after all.

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