New Extinction Theory: 'Big Chill' After Asteroid Impact
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[url=http://www.cbsnews.com/news/freezing-darkness-killed-the-dinosaurs-research-says/]Source[/url]
[quote]When a giant asteroid careened into Earth about 66 million years ago, the enormous collision led to the formation of an airborne “curtain” of sulfate molecules that blocked the sun’s light and led to years of freezing cold and darkness, a new study finds.
The finding shows how these droplets, or aerosols, of sulfuric acid formed high in the atmosphere, and likely contributed to the deaths of 75 percent of all animals on Earth, including nonavian dinosaurs such as Tyrannosaurus rex and long-necked sauropods, the researchers said.
Earlier studies suggested that the dino-killing asteroid kicked up dust and debris that hung in the air and blocked sunlight in the short term. But by using computer simulations, the researchers of the new study showed how droplets of sulfuric acid contributed to long-term cooling. [Wipe Out: History’s Most Mysterious Extinctions]
Moreover, the sudden, drastic drop in temperature likely caused the surface of the oceans to cool, which would have massively disturbed the marine ecosystems, the researchers said.
“The big chill following the impact of the asteroid that formed the Chicxulub crater in Mexico is a turning point in Earth history,” the study’s lead researcher Julia Brugger, a climate scientist at the Potsdam Institute for Climate Impact Research (PIK) in Germany, said in a statement. “We can now contribute new insights for understanding the much debated ultimate cause for the demise of the dinosaurs at the end of the Cretaceous era.”
Brugger and her colleagues employed a type of computer simulation typically used for climate modeling. The model showed that gases containing sulfur evaporated during the violent impact. These sulfuric molecules were the main ingredients that blocked the sun’s light on Earth and led to plummeting temperatures, they said.
For instance, before the asteroid hit, the tropics were an average temperature of [B]81 degrees Fahrenheit (27 degrees Celsius)[/B]. But after the massive impact, the average temperature was [B]41 F (5 C)[/B], the researchers said.
“It became cold, I mean, really cold,” Brugger said. Globally, temperatures fell at least 47 F (26 C). For at least three years following the asteroid’s crash, the average annual temperature fell below freezing, and the polar ice caps grew in size.
“The long-term cooling caused by the sulfate aerosols was much more important for the mass extinction than the dust that stays in the atmosphere for only a relatively short time,” study co-researcher Georg Feulner, a climate scientist at PIK, said in the statement. “It was also more important than local events like the extreme heat close to the impact, wildfires or tsunamis.”[/quote]
Fascinating study within, I'd highly recommend it.
good to know for when we have to geoengineer them to fucking halt climate change.
I thought this has been the prevailing theory for a while
[QUOTE=Megadave;51712212]Weird, I always thought this is the way it went.[/QUOTE]
It's a "new theory" as there were mumblings over a great heat death. Rather than a single impact blotting out the sun, it was a massive shower that roasted the surface of the planet alive, and then shattered it with brutal cold, essentially ending the Cretaceous in a heartbeat.
This one, instead, goes back to the slow death theory where the Cretaceous slowly crawled into its own grave.
[QUOTE=Sableye;51712204]good to know for when we have to geoengineer them to fucking halt climate change.[/QUOTE]Geo-engineering is almost too fucking dangerous as climate change, Befeore we do anything we would have to study it Hard.
Some Scientists even want to induce a nuclear winter, not joking.
[QUOTE=Hobo4President;51712217]I thought this has been the prevailing theory for a while[/QUOTE]
Also what makes this different is the presence of sulfuric acid and other sulfates, rather than the generic "lots of dirt"
[QUOTE=Zillamaster55;51712225]It's a "new theory" as there were mumblings over a great heat death. Rather than a single impact blotting out the sun, it was a massive shower that roasted the surface of the planet alive, and then shattered it with brutal cold, essentially ending the Cretaceous in a heartbeat.
This one, instead, goes back to the slow death theory where the Cretaceous slowly crawled into its own grave.[/QUOTE]
Ah so more than a sudden cooling causing rapid extinction it happened over a longer period leading to death of the larger animals?
[QUOTE=Hobo4President;51712238]Ah so more than a sudden cooling causing rapid extinction it happened over a longer period leading to death of the larger animals?[/QUOTE]
Essentially. Paleontologists still argue over how long the "End" lasted, as there's evidence for both sides.
One side says that the Dinosaurs died out in less than a decade (some say in an instant) after ludicrously rapid climate heating, cooling, and then deaths of ecosystems.
Other side says that the Dinosaurs took possibly centuries to die out as the world itself was choked to death by a combination of issues (climate change and plus a pissed off rock)
Although their evidence seems to assess some new properties, I was under the impression that this was fairly standard in models of the K-Pg extinction event (3-to-30 years in this study isn't particularly different from the 6-8 month estimate of snow-forming cold by the Animal Armageddon "documentary" series in the grand scheme of things, for example), so I don't see how the theory itself constitutes being considered new unless the implication is that all vegetation was in such a shock from the temperature that there was no blackout period of starvation preceeding it, which doesn't seem entirely practical to explain the consistent film of iridium present throughout most of the world which would be more in line with a time of complete darkness. (Not to mention a long-term period of cold should have theoretically harmed organisms such as amphibians and crocodilians far more than if it was a short, 1-3 year mass death, as crocodilians could for example get by on one-to-two meals per year, whereas they'd suffer from the extremely low temperatures. Crocodilians alive today are very cold intolerant and in just the short span of time since the Eocene have been relegated from living in an ice-free arctic to barely ~30*N latitude worldwide.)
[QUOTE=Megadave;51712212]Weird, I always thought this was the way it went.[/QUOTE]
Yeah, what were we thinking it was before, this?
[media]https://www.youtube.com/watch?v=aeNZbY-7O5Y[/media]
I guess water levels dropped quite a bit with everywhere freezing up and the ice caps growing significantly larger.
I feel like the world could use a 'big chill' right about now what with how much people are riled up.
[QUOTE=Hogie bear;51714125]I feel like the world could use a 'big chill' right about now what with how much people are riled up.[/QUOTE]i mean, yeah, that's what the votes for Giant Meteor were for, right?
Wasn't this a theory for over a decade now at least? IIRC this is why the only animals that survived that were larger than a house cat were marine life.
This reminds me of a co-worker who once told me he had evidence (never saw it) that dinosaurs were killed in Noah's Flood, and not as a result of an impact from a comet or asteroid.
I told him there's not enough water on this planet in any location or form to flood the Earth to the levels described in the Bible, and he said this:
"Well what happened was, the Earth was hit by a comet, or an asteroid, and it kicked up a huuuge dust cloud, which shielded the Earth from the Sun's rays, which caused the Earth to cool, [B]and it shrunk[/B]."
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