stoutfellow

Still plowing my way through Lyell. The last section was a discussion of the origin of the energy involved in earthquakes and volcanoes. Lyell presents, and then dismisses, the idea that the interior of the planet is molten, and the heat works its way up from below. (His objection is that temperature ought to equalize throughout the planet, given enough time. I'm not sure what the answer to that is. I have a textbook on physical geology around here somewhere, which I should maybe read after finishing with Lyell.) He seems a bit more receptive to chemical or electrical origins, especially given the then-new discoveries about the relation between magnetism and charges in motion.

The section I'm reading now is on the biosphere; Lyell here tentatively accepts Lamarckian evolution, although he doesn't believe in monogenesis - plants are clearly, he thinks, a separate creation from animals, for example. Evidently this edition predated his acquaintance with Darwin's work. Should be interesting to see what lines of inquiry he follows in this area.

In the section of Lyell that I'm currently reading, he goes into much detail concerning the effects of volcanic eruptions, starting with Vesuvius and Etna, proceeding to Iceland and Chile, and ending with the great Tambora eruption in 1815. (He's restricted, somewhat, by the need to have details recorded by observers of a scientific bent.) He does not, however, mention the meteorological consequences of that last - the legendary Year Without a Summer, when harvests all across the Northern Hemisphere failed because of the reduction in sunlight induced by the debris of the eruption. I can see two possible explanations.

1) He wasn't interested in the meteorology; his concern was establishing that known geological phenomena, given enough time, could account for all the changes in the geological record, without recourse to global catastrophes.

2) He didn't make the connection between the two. After all, it's not obvious that a volcanic eruption in the East Indies could cause crop failures in Europe.

The question that occurs to me, then, is this: when did someone make the connection? I have a vague memory that modern meteorology, with its fronts and jet streams and whatnot, didn't arise until the early twentieth century, but would that knowledge have been necessary? (There was a book I read forty-some years ago, a treasury of snippets of scientific history; it included some stuff about the life of Louis Agassiz, about the emergence of the Paricutin volcano, and, if I remember correctly, about the introduction of the idea of fronts. I don't remember the title or the editor; the book vanished from my hands long ago. I wish I still had it, for nostalgia's sake if no other.)

Charles Lyell's Principles of Geology is the other major nonfiction work I'm currently reading. In some ways, it's a window into the past; the main point of the book is to stake out and defend a position in a controversy that has been long since resolved. One of the prevailing theories of geology in Lyell's day was catastrophism, holding that the Earth had alternated between long periods of geological quiescence and brief periods of immense upheaval, in which the shape of the continents changed radically and life was virtually extinguished, to be followed by a new creation of life. Lyell argued for the uniformitarian position, that the data could be equally well explained by the assumption that the geological processes at any time in Earth's history were the same, in quality and intensity, as those now perceived; all that was needed for radical upheaval was the passage of sufficient time.

One of Lyell's biggest headaches had to do with the changing patterns of life found in the fossil record. He was at times reduced to pointing out that the record was fragmentary enough that we couldn't be sure that, e.g., there were no mammals in the Carboniferous. Darwin's work on evolution must have come as a great relief to him; he and Darwin were friends and intellectual allies, and he was an early proponent of the Darwinian position.

The only large-scale geological processes Lyell could point to were uplift and subsidence (and you can see the same ideas in, e.g., The Voyage of the Beagle); these were the source of such proposals as the existence of a lost continent of Lemuria in the Indian Ocean, to account for the presence of lemurs in Madagascar and India but nowhere in between. (Many other land bridge proposals were in vogue in the following century or so.) Plate tectonics, of course, does a much better job of explaining such things.

Uniformitarianism carried the day, eventually. It's interesting the ways that modern theory diverges from it, though. First, in the Hadean Eon, the geological processes were definitely not those of the present; it's not even clear that plate tectonics had started yet. More broadly, the study of the Great Extinctions bears a passing resemblance to catastrophism, with its continental-scale volcanic eruptions and the occasional asteroid. (Of course, the catastrophe causing the current Great Extinction is not geological in origin....)

It's an interesting read; Kindle says I'm only about 19% of the way in. I'll be interested in his discussion of the appearance of humanity, which even he had to admit was a recent phenomenon.

This presents a wonderful little discovery about gorillas and food. Just neat.

(H/t to rfmcdpei.)

Clayton Kershaw, ace pitcher for the EBE - three-time Cy Young winner, 2014 MVP, five-time All-Star - is the great-nephew of Clyde Tombaugh, discoverer of the ex-planet Pluto.

Small world (pun only semi-intentional).

Oliver Sacks has died.

If you haven't yet read The Man Who Mistook His Wife for a Hat, do so. Now.

Then look for something else he wrote. I don't care what. Repeat as necessary.

:raises glass:

I'm reading Darwin's paper on earthworms. At one point Darwin describes the worms' habit of plugging the mouths of their burrows with leaves. Sometimes, he writes, they use pine needles - the type that come in pairs, joined at the base.

As the sharply pointed leaves diverge a little, and as several leaves are drawn into the same burrow, each tuft forms a perfect chevaux de frise.

Not being familiar with that last phrase, I looked it up online; Wikipedia provides a helpful picture. They are precisely the sort of barricade used by fortresses in Skyrim.

Darwin and video games. How 'bout that?

So the big astronomical news is that in about four billion years the Milky Way and the Andromeda galaxy will collide and merge into a single elliptical galaxy. There's been some mention of Andromeda's satellite, M33, which will also get swallowed up (and may collide with the Milky Way first). Here is a good reference, with an animation.

But nobody seems to mention the Milky Way's satellites: the Greater and Lesser Magellanic Clouds, plus eight or so less famous dwarf galaxies. What happens to them? Anybody know?

Emily Lakdawalla has an interesting article up about some of the moons of Saturn, including some remarkable photos of Hyperion (which resembles a sponge) and Atlas (which is saucer-shaped). Take a look.

This one's not about Buster and Gracie. Here's an interesting article about the evolution of dogs. The first part is a bit commonplace, but the section towards the end on the feral dogs of Moscow, especially the "beggar dogs", is fascinating.