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Scientists Discover New Evidence of the Asteroid That Killed Off the Dinosaurs (wsj.com)
82 points by daegloe 13 days ago | hide | past | web | favorite | 33 comments

This is another fascinating window on the impact:


"the first mass death assemblage of large organisms anyone has found associated with the K-T boundary"

And I've read (can't find the link now) that had the impact happened ten minutes sooner or ten minutes later the effect would have been much less, because the sulfur-bearing rocks wouldn't have been hit thus the climate-changing aerosols would not have been released.

An article from The New Yorker on the same thing:


The big concern at the time was that nothing about this find had been published in academic publications, just The New Yorker, Fox News, and other news outlets. I haven' heard anything since April.

Here's the paper:

"A seismically induced onshore surge deposit at the KPg boundary, North Dakota"

Robert A. DePalma, Jan Smit, David A. Burnham, Klaudia Kuiper, Phillip L. Manning, Anton Oleinik, Peter Larson, Florentin J. Maurrasse, Johan Vellekoop, Mark A. Richards, Loren Gurche, and Walter Alvarez

PNAS April 23, 2019 116 (17) 8190-8199


Here's the paper:

The first day of the Cenozoic

Sean P. S. Gulick, Timothy J. Bralower, Jens Ormö, Brendon Hall, Kliti Grice, Bettina Schaefer, Shelby Lyons, Katherine H. Freeman, Joanna V. Morgan, Natalia Artemieva, Pim Kaskes, Sietze J. de Graaff, Michael T. Whalen, Gareth S. Collins, Sonia M. Tikoo, Christina Verhagen, Gail L. Christeson, Philippe Claeys, Marco J. L. Coolen, Steven Goderis, Kazuhisa Goto, Richard A. F. Grieve, Naoma McCall, Gordon R. Osinski, Auriol S. P. Rae, Ulrich Riller, Jan Smit, Vivi Vajda, Axel Wittmann, the Expedition 364 Scientists

Proceedings of the National Academy of Sciences Sep 2019, 201909479; DOI: 10.1073/pnas.1909479116


I was curious about what you meant by 10 minutes sooner or 10 minutes later, so I found this [1]:

> The discovery of the Chicxulub crater dramatically enhanced the community’s ability to evaluate the environmental effects of an impact at the K-T boundary, because both the geographic location of an impact site and the target rocks involved in an impact can affect the environmental outcome. For example, rocks composed of the mineral anhydrite in the Chicxulub target sequence imply that sulfate aerosols were injected into the stratosphere, affecting the radiative budget of the atmosphere (heating the stratosphere while cooling the Earth’s surface) before settling to the troposphere where they were washed out as acid rain.

[1] https://www.lpi.usra.edu/science/kring/Chicxulub/global-effe...

I assume the parent means that the same asteroid, on the same trajectory, but delayed or hastened by 10 minutes will hit a completely different spot on the planet.

HAd to look for K-T boundary : Cretaceous–Tertiary (K-T) boundary :-)

>wiping out the dinosaurs and three-quarters of all other life.

The interesting thing about mass extinctions is that they're worse than you imagine from the way scientists commonly phrase it. 75% of species on earth were driven extinct, but that doesn't mean it killed 75% of the trees and bushes and animals and fish. It means it killed every single member of 75% of those species. If you counted the gross number of macroscopic living things before and after, the real portion of them killed was much higher than 75%.

For some reason I had thought the impact crater was in the US - perhaps that was a different impact

Perhaps you're thinking of Barringer Crater near Flagstaff, Arizona: https://en.wikipedia.org/wiki/Meteor_Crater

"The dinosaur-killing asteroid, estimated to have been up to 50 miles or so across,"

I thought it was 6 miles across. Have I missed some research on this?

Between 6.8 and 50 according to wikipedia:


Just wondering...if the dinos had survived, would they have evolved higher intelligence and complex societies or would they be similar to modern reptiles/crocs/turtles and fish(which are as old no?) in terms of intelligence?

This may sound like nitpicking, but it isn't: the dinos have survived. All birds are dinosaurs. In fact, birds are extremely closely related to the dinosaurs that were long conjectured to have the highest cognitive abilities [1].

Some birds arguably have higher intelligence and form complex societies. But it was the primate group that developed the "most complex" society. This despite the fact that birds like primates are visually oriented, highly vocalized, take extensive care of their young, and many are already adopted to live in complex societies. It could be that the manual dexterity of primates, as well as the mammalian gestation period ('pregnancy') and its ability to have more developed children at birth could be further required factors that led to societies of human complexity.

You never know what 65 million years of uninterrupted evolution would have produced, but based on the way birds evolved I don't believe we would have had a dinosaur Hacker News in this alternate history.

[1]: https://en.wikipedia.org/wiki/Troodontidae

If the event didn't occur, dinosaurs may not have all just become birds. The evolution of the animal eco system would have been very different -- but maybe still reaching the same result.

> If the event didn't occur, dinosaurs may not have all just become birds.

I'm not trying to suggest that. I'm just saying that we don't know enough, but that based on the limited things we do know (birds never got to primate level societal complexity), we can hypothesize that dinosaurs would never have made it.

It could well be that some other dinosaur subfamily could have taken a turn towards becoming a complex society, but I wouldn't have bet on the ankylosaurs, the sauropods or the ornithopods either for this.

A talking bird can teach other birds to talk. But those birds can't teach others to talk

Maybe not a fact but Macaws click their talons much like a dino, atleast in the way the Dino's were presented in Jurassic Park. But they do the head bobbing motion too.

A talking bird can have a sense of humor. My macaw would call the dog to the cage. Throw food at him and then laugh. Sometimes in a British accent. I have no idea where that came from.

And they are pretty territorial. I have a scar to prove it.

Granted this is mostly anecdotal from having a macaw for thirty years

Birds are like the dinosaurs in Jurassic park because those fictional dinosaurs were modelled on birds.

I wasn't just referencing jp in my comment. Just one single observation. The rest were unrelated due to me having a macaw for thirty years.

Thanks for incorrecting me

maybe? but in my non-expert opinion, probably not.

intelligence doesn't seem to be correlated with the age of the species or recent lineage from what i understand.

in the water, sharks are extremely old, almost reaching back to the dinosaur ages, but they are wrecked in intelligence by orcas, who came much later.

plus, intelligence, or at least the further development of society and technology is solely due to the ability to manipulate objects. for example, i strongly believe that if you took an orca brain and gave it human-like manipulation tools and moved it to land that you would have a homosapiens competitor.

I believe it's certainly possible that they could have, but it's also possible that they wouldn't have. I think it's a matter of probability more than anything. It's a common misconception that humans are the pinnacle of evolution -- that we're somehow that most advanced in the lineage of evolution. People often misinterpret "survival of the fittest" to imply that we, humans, are the fittest because of our intelligence. In the context of what's on Earth today, we're no more the fittest than modern day ants. "Fittest" should be thought of "fittest for [X] environment". If the dinosaurs hadn't died out, it's quite possible that one or more species would have evolved intelligence that made them fit for their niche, but it's quite possible that intelligence would never have made any of them the fittest for their niche, and thus not evolved into something more.

Well plenty of similar animals that were around at the same time such as Crocodiles have not. Unless crocs reside in our sewers watching, waiting and plotting our downfall

"Drilling into the seafloor off Mexico, scientists have extracted a unique geologic record of the single worst day in the history of life on Earth, when a city-sized asteroid smashed into the planet 65 million years ago, wiping out the dinosaurs and three-quarters of all other life."

I wonder if we can learn from that disaster in order to deal with climate change? Seems to be at a similar scale of what may be threatening us.

Not to troll here but I'd be interested in you expanding upon what you mean by this.

The reason I say that is the asteroid impact was, by every definition, pure chance in that earth was in the way when it flew through space across our orbital path.

(Not wanting to get into a debate about climate change / climate change denial here...) Climate change is something that is happening due to somewhat preventable actions, not chance.

I'm curious what you think we could learn from it.

I think the idea is that you should try to prepare for disasters and be able to mitigate them.

Basically, the reason most of the dinosaurs went extinct is because they were foolish and short-sighted and didn't bother to develop a serious space program so they could detect, track, and then intercept inbound asteroids. They lived at a time when there were surely more asteroids hitting the Earth than now (the system was younger, so there was more debris flying around), so they surely had more warning than we do: craters, smaller impacts, etc. They ignored all this, so when a really big asteroid came along, they had no way of redirecting it, or even detecting it beforehand.

We're not doing much better.

We can detect some asteroids, but are we able to intercept and redirect them? No, because we haven't bothered investing much money in a program to develop that capability. Yet we've had plenty of impacts and near-misses. One hit in Russia a few years ago, injuring 1000 people. One flies by pretty frequently, and I think one is supposed to come extremely close this month. Where's the program to intercept these things well ahead of time and redirect them?

Climate change isn't that different, except that it isn't just some natural occurrence, it's something we're mostly doing by ourselves. So we're studying it some, we've made predictions about what the effects will be based on evidence from earlier times, yet we absolutely refuse to make any real changes to attempt to avoid this fate.

In short, we really aren't much smarter than the dinosaurs.

> They lived at a time when there were surely more asteroids hitting the Earth than now (the system was younger, so there was more debris flying around), so they surely had more warning than we do: craters, smaller impacts, etc.

This is a tangential point, but they weren't living in an appreciably younger solar system. 65 million / 4.5 billion is ~1.5%. So, the solar system (and the Earth) was 98.5% of its current age.

Maybe not, but it was still a little bit younger, so there should have been somewhat more asteroid strikes, even if only by a couple percent.

Moreover, the dinosaurs were around for over 150 million years. Hominids have been around for only about 2M years, and modern humans only about 200k. They had loads of time to observe asteroids, realize they're a threat to their existence, and develop advanced technology and an effective and credible space program to deal with the threat. But they were just too lazy, or too busy fighting each other, to bother doing this, and look what the consequences to them were.

Probably not much. What we are currently doing is more similar to the less sudden end-permian extinction, which nonetheless was quite a bit more deadly than the K/Pg extinction with an extinction rate in the 90% range.

That doesn’t seem right. That thing vaporized Rick, ignited the atmosphere, kicked up massive amounts of earth into the atmosphere and caused huge waves in the oceans (tsunamis isn't even the right word).

> vaporized Rick

Poor Rick :( But yes, it took a while for the climate to go back to normal after that.

His Morty was happier almost instantly though - he was a particularly traumatic Rick, which is saying something!

I laughed.

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