Comment by conductr
7 days ago
My son is a dinosaur enthusiast to say the least.
At some point, well into his accumulation of Dino facts we read an old book I had as a kid (mid 80s) and the book says all kinds of weird stuff I forget but abruptly ends with “they went extinct and we may never know how” and my son (age 4 at the time) is at a loss for words, “it was a asteroid dad, what dummy wrote this book?” For weeks he’d randomly look at me, “hey dad, remember that book that didn’t even know how dinosaurs went extinct? Sigh with disappointment.”
I hadn’t realized this was such a contemporary discovery that it wasn’t even part of my own initial understanding and education on the topic.
This led to finding a fun easter egg Googling "Chicxulub Crater" https://www.google.com/search?q=Chicxulub+Crater
They are not extinct. There are a few making noises in the trees in my backyard now, and I dined on some dino-meat today!
omnom gonna get me some Kentucky Fried Dinosaur!
It might be more complicated than that. While the Chicxulub impact probably played a big role in the Cretaceous–Paleogene extinction event, there are potentially other sources of why it was as bad as it was. The eruption of the Deccan Traps may have also played an important part in the mass extinction event.
https://en.wikipedia.org/wiki/Deccan_Traps
https://en.wikipedia.org/wiki/Cretaceous%E2%80%93Paleogene_e...
Sure, but if a cancer patient gets shot, "he was already sick" isn't a legal defense.
Which one is the gun and which one is the cancer in this scenario? Would the cancer patient survived the gun shot if they weren't already weakened from cancer treatments and disease progression? Would they have survived the cancer if they didn't experience the trauma of the gunshot wound?
I don't think we definitively have the answers to that question IRT what killed the dinosaurs.
I started school in the 90s and mostly remember it as "we're pretty sure it was a meteor but it's really hard to know for sure", but looks like 1980 was when it was first seriously theorized.
Its definitely one of those things where every once in a while I'll be reading about some historical figure and remember that they'd never been able to hear of dinosaurs.
I thought that it still isn’t really known? Is is one common theory, but we have just probabilities to play with.
Finding the impact crater pretty much cemented it. It absolutely happened. The remaining questions are around if the impact was enough to trigger the extinction on its own or if other factors compounded the problem.
There's a strong case to be made that the impact not only was enough to trigger the extinction, it happened in 1 day. The theory is that the ejecta from the impact was voluminous enough that it was sent into space and then spread around the Earth. On reentry it heated the atmosphere to thousands of degrees. So animals in New Zealand that likely didn't even feel the impact died when the air was too hot to breath. The only survivors were things in burrows or nests or under water.
> The remaining questions are around if the impact was enough to trigger the extinction
Well, in the sense that we can never be sure of anything, yeah. But it not being enough is a really extraordinary idea.
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Descartes would like a word as well, I'm sure. The big difference in the impact theory story is it's the first time we had enough evidence about any of the possibilities that widespread consensus (but not universal agreement it is the sole possible cause) was reached. Prior to that we weren't really sure if we'd even be able to get to that level about it. At least if the theory is replaced it'll be about something we see even clearer evidence of instead of "I dunno, could possibly have been...".
I think the majority of palaeontologists now accept the idea. Alternative ideas get disproportionate attention in popular articles.
The geological record of the K-T boundary is very hard to argue with
Much like gravity, it is only a theory.
It'll be settled when the generation of researchers who fought over it retire/die off. The short TL;DR is that the guy who came up with the asteroid theory knew basically nothing about paleontology and paleoclimate, was way outside of his depth (he was a physicist that worked on the Manhattan project). He then made some pretty wild claims given the evidence that was available. When criticized by people who actually knew the field, he would personally attack them and drive public support against them as dinosaurs in a field of dinosaur research.
Then the Chicxulub crater was found and dated to basically the exact same time as the K-T extinction event to within experimental error. So I guess the asshole was right?
Except science doesn't work by smoking guns, as appealing as that would be. There are a lot of contradictory evidence. Better instruments and more careful data collection shows that in some places the fossil record stops prior to the impact layer. Also the fossils are of animals you would expect of an extinction event already ongoing. Oh, and coincidentally right before the Chicxulub impact India hit the continent of Asia and the Deccan Traps started spewing CO2 and other gasses into the atmosphere in volumes that put human-caused climate change to shame. The ocean was acidifying and ecosystems collapsing. Is it really fair to say an asteroid impact killed the dinosaurs, when they were already on the way out?
IMHO the current best theory is the "one-two punch" that the Deccan traps eruptions basically put every large species on extinction watch, then the asteroid impact happened and finished the job. But it has become so political within that research community that people just aren't rational about the evidence, on either side.
The Alvarez hypothesis is notable not just because of its power in explaining the Cretaceous mass extinction, but because of its Copernican-like effect on paleontology.
Up to that point, it was a matter of belief among paleos that bolides were not a significant factor in the history of life. Essentially, that the Earth did not experience frequent or significant impacts after the initial formation of the solar system.
The evidence supporting Alvarez became so compelling that it not only became accepted as the K-T cause, it opened the door to considering bolides for all sorts of previous extinctions--an idea explored by Raup in his book Extinction. It made "sudden catastrophes" acceptable as a serious research subject for the first time since Lyell.
Prior to Alvarez, it was a matter of faith that the K-T boundary must have a solely terrestrial explanation, and the Deccan Traps were elevated to the most likely candidate. But it just shifted the need for explanation--why was there sudden globally catastrophic vulcanism? You say "India hit Asia" but that was not a sudden thing, in fact it's still happening today. Hot spots are still active today. It never really worked, but it was the best they had (or were willing to consider at the time).
The short TL;DR is that the guy who came up with the asteroid theory knew basically nothing about paleontology and paleoclimate, was way outside of his depth (he was a physicist that worked on the Manhattan project).
Eh, that's underselling Luis Alvarez a bit. He wasn't just "a physicist," he was a Nobel laureate and arguably one of the twentieth century's few Renaissance men. My favorite Alvarez hack was when he used muon imaging to 'X-ray' the Great Pyramid. He didn't find any hidden chambers, but later researchers did.
In the Alvarez mass-extinction hypothesis, he simply followed where the evidence led, unlike the supposed professionals in the field.
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When I was a kid I loved "Dinosaur Time" by Peggy Parish (and illustrated by Arnold Lobel). Originally published in 1974 it ends, "Dinosaurs lived everywhere for a long time. Then they died. Nobody knows why. But once it was their world. It was Dinosaur Time."
There was a revision to the book (not sure the date) with changes to the text and an expanded author's note at the end that talks about the new things we understand about dinosaurs including how Brachiosaurus are no longer believed to have spent their time in water to support their weight and how it's now believed an asteroid killed off the dinosaurs.
Original: https://archive.org/details/dinosaurtime00pari
Fantasia gets this wrong, depicting the dinosaurs dying from lack of water.
But there were blonde centaurs, right?
Right?
I remember way back when I was in the 5th grade, I read an old book my school had about the planets, and it talked about how some astronomers are looking for a ninth planet, one even further away than Neptune.
Kind of funny, that now due to astronomer's shenanigans, we're back in the same position.
Nothing new was discovered, there is no better evidence now than when that book was written in the 80s. We're just living in a new era of scientific understanding where it is taboo to say or write that any question is not answered.
I remember the first time Brontosaurus was Brontosaurus.