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Ep. 36, Page 51
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Comic 2828 - Ep. 36, Page 51

1st Apr 2019, 9:31 PM in Episode 36 :: Save My Place | Load My Place
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Author Notes:

smbhax 1st Apr 2019, 9:31 PM edit delete
smbhax
The New Yorker recently posted a fascinating article called The Day the Dinosaurs Died, about somewhat unorthodox young paleontologist Robert DePalma's discovery of a site in Nebraska that may be a direct recording of the meteor-spawned global cataclysm 65 million years ago wiping out life on Earth.

The meteor strike was so powerful ("the energy released was more than that of a billion Hiroshima bombs, but the blast looked nothing like a nuclear explosion, with its signature mushroom cloud. Instead, the initial blowout formed a 'rooster tail,' a gigantic jet of molten material, which exited the atmosphere"—the BBC, incidentally, got this exactly wrong, posting a mushroom-cloud-type effect in their thumbnail of an article about the impending release of DePalma's group research paper) that


"Some of the ejecta escaped Earth’s gravitational pull and went into irregular orbits around the sun. Over millions of years, bits of it found their way to other planets and moons in the solar system. Mars was eventually strewn with the debris—just as pieces of Mars, knocked aloft by ancient asteroid impacts, have been found on Earth. A 2013 study in the journal Astrobiology estimated that tens of thousands of pounds of impact rubble may have landed on Titan, a moon of Saturn, and on Europa and Callisto, which orbit Jupiter—three satellites that scientists believe may have promising habitats for life. Mathematical models indicate that at least some of this vagabond debris still harbored living microbes. The asteroid may have sown life throughout the solar system, even as it ravaged life on Earth."


Another interesting space-related note from the article: "He'd also found scores of beautiful examples of lonsdaleite, a hexagonal form of diamond that is associated with impacts; it forms when carbon in an asteroid is compressed so violently that it crystallizes into trillions of microscopic grains, which are blasted into the air and drift down."

That's about all the space-specific stuff; I suppose I should include a note of caution about reading the very lengthy article in full: it paints a blow-by-blow, extremely harrowing picture of what was pretty much the end of the world as it existed to that point. I was haunted by brain-conjured images of it for days after reading the article. In fact, I'm going to roll in some quotes about it here, so maybe just skip the rest of this blog entry if it all sounds a bit much to you. : o

Still here? Okay then.

Because lines like "more than 99.9999 per cent of all living organisms on Earth died" kind of stick around in your head, you know? But how did they die? Ah.


"The asteroid was vaporized on impact. Its substance, mingling with vaporized Earth rock, formed a fiery plume, which reached halfway to the moon before collapsing in a pillar of incandescent dust. Computer models suggest that the atmosphere within fifteen hundred miles of ground zero became red hot from the debris storm, triggering gigantic forest fires. As the Earth rotated, the airborne material converged at the opposite side of the planet, where it fell and set fire to the entire Indian subcontinent. Measurements of the layer of ash and soot that eventually coated the Earth indicate that fires consumed about seventy per cent of the world’s forests."


That isn't even the most vivid stuff, though: that comes from working out how, at this dig site in Nebraska, jumbled, torn-up bits of Cretaceous life (this was the precise moment the Cretaceous ended; DePalma, as the writer watched him work, even found a small mammal's burrow in the fossilized mud layers: surviving, it would seem, the end of the Cretaceous, it had dug into the solidified mud for protection, and died in its burrow in the Paleogene, where it remained for 65 million years, until he found and carefully extracted it—in fact, its whole burrow—for analysis) ended up being preserved in almost minute-by-minute layers of sediment, laid down as nearly unimaginable violence completely destroyed the area over what may have been an hour or so of absolute disaster, with a fine rain of molten rock—yes, blasted up from the impact in what is now the Gulf of Mexico, near an eventual Mayan town of Chicxulub, 3000 miles distant from Nebraska—seen now embedded in the layers of mud, and fossilized fish gills, as glassy beads called microtektites—coming down, probably setting fire to everything flammable while an incredibly powerful quake shot through the Earth, shaking the surface so strongly that local bodies of water agitated violently, surging back and forth so powerfully that many of the fossilized creatures were torn apart in large pieces before they were buried; they even found one large ancient fish embedded in another, their bodies thrown together with such force that the sturgeon's bony back plates impaled the paddlefish.

The theory proposed by the researchers is that what made this site possible, with its unique layers of fossils and embedded microtektites, was that it was at just the right distance to be reached by the asteroid impact's seismic waves and aerial debris at the same time, and that a local body of water was in just the right position to wash over the area repeatedly when agitated. Although the site, which DePalma dubbed "Tanis," is near the edge of what was at that time a large, shallow inland sea stretching right up through North America from the Gulf, "the KT tsunami, even moving at more than a hundred miles an hour, would have taken many hours to travel the two thousand miles to the site. The rainfall of glass blobs, however, would have hit the area and stopped within about an hour after the impact." "[UW geophysicist Mark] Richards had previously estimated that the worldwide earthquake generated by the KT impact could have been a thousand times stronger than the biggest earthquake ever experienced in human history. Using that gauge, he calculated that potent seismic waves would have arrived at Tanis six minutes, ten minutes, and thirteen minutes after the impact."

So, the next time you feel like you've just had a rough hour or so, think about that scene from 65 million years ago. Or maybe don't. : o