• kevinkeller 8 days ago |
    I love this type of articles where we can reconstruct what happened so long ago just based on careful observations.

    Some other instances I've come across:

    * The K-Pg extinction event that wiped off dinosaurs had the impact it did because the asteroid happened to impact a shallow water region. This kicked up a lot of sulfur (in gypsum) that further affected global climate: https://en.wikipedia.org/wiki/Chicxulub_crater#Effects

    * Earth likely had rings ~466M years ago. We deduced this by looking at impact craters from that time period, and seeing that they all lie near the equator (accounting for continental drift): https://www.sciencedirect.com/science/article/pii/S0012821X2...

    * Earth's rotation period was probably frozen at 21h, ~600M years ago, likely due to interaction between lunar and solar tides. This resonance could have been broken by ice ages (!!!). Amazing to think that global climate affects earth's rotation: https://en.wikipedia.org/wiki/Earth%27s_rotation#Resonant_st...

    • thangalin 8 days ago |
      > reconstruct what happened so long ago just based on careful observations.

      Me too! My book is filled with them. Like how minerals in lava, affected by Earth's magnetic field, lock into place while cooling, which provides us with yet another cross-check for radiometric dating. See page 23:

      https://impacts.to/downloads/lowres/impacts.pdf

    • chiefalchemist 8 days ago |
      Not to nitpick but the dinosaurs were on already on the way out, the asteroid merely finished them off early.

      https://www.theatlantic.com/magazine/archive/2018/09/dinosau...

      • Arech 7 days ago |
        To the best of my knowledge not everyone agrees to that hypothesis. One of the strongest arguments against it is that paleontological evidence is always incomplete. Holes in it that are treated in favor of the hypothesis are actually smaller or comparable to holes that appear just due to incompleteness.
        • chiefalchemist 6 days ago |
          Read the article. That's the subplot. We get to see just how non-scientific science really is. The true and current evidence points to an asteroid being the final blow to an already declining environment. But the status quo narrative so strong that egos and biases override facts.
    • Timwi 7 days ago |
      The dinosaurs were not “wiped off”, by which I mean they are not extinct. This is an extremely widespread misconception that popular science articles like this one keep perpetuating. We should do better and help people understand that (some) dinosaurs survived and evolved into modern birds. Birds are dinosaurs. Dinosaurs are alive today.
      • Qem 7 days ago |
        When referring to dinosaurs, most people are thinking about non-avian, teethed dinosaurs anyway.
        • Timwi 5 days ago |
          I get that, but most people don't know that birds evolved from dinosaurs that survived the asteroid (which I think is both interesting and important to know) and I think it's the responsibility of science communicators to... communicate that.
      • asah 7 days ago |
    • datameta 7 days ago |
      Here is the Chixculub impact effect in realtime simulated as happening in today's world: https://youtu.be/ya3w1bvaxaQ?si=S-jmFegMo63HKzID
  • jeffbee 8 days ago |
    The paper also mentions that, at the time, "dinosaur killer"-sized objects hit the Earth every 15 million years on average, which must have been sort of disruptive.
  • 1970-01-01 8 days ago |
    Vote for Giant Meteor 2028!

    https://votegiantmeteor.com/

  • hehehheh 8 days ago |
    When is the next one coming? Or what is the probability distributuon like?
    • patrickthebold 8 days ago |
      It's a poisson distribution.
      • dataflow 8 days ago |
        Have the data actually been fit a Poisson distribution? Or is this is just a guess assuming constant rate and independence?
        • glial 8 days ago |
          No natural phenomena ever exactly fits any probability distribution.
          • dataflow 8 days ago |
            Right but I'm saying do we have data showing it's even close? (Genuinely asking, I have no idea.)
          • Q_is_4_Quantum 8 days ago |
            except the emission spectra from atoms :)
      • nverno 8 days ago |
        I imagine it is more of an exponential decay mixed with poisson since strikes were far more common back in the day. Also, I'd guess an exponential decay in the expected size of impactors over time as they've been smashing themselves into pieces.
      • Arech 7 days ago |
        Likely it isn't, because the Solar system today and 3Bln years ago are two very different systems.
    • rad_gruchalski 7 days ago |
      If things go sideways in 2029, the next one comes in 2036.
  • dang 8 days ago |
    The paper is at https://www.pnas.org/doi/10.1073/pnas.2408721121. We've adopted its title above.
  • Timwi 7 days ago |
    The article perpetuates the widespread misconception that dinosaurs are extinct. In reality, (some) dinosaurs survived and evolved into modern birds. Everything from penguins to ostriches, hummingbirds to albatrosses and woodpeckers to eagles is a dinosaur.

    Science communication should do better and clear up this misunderstanding.

    It would be so much cooler to say that the asteroid killed the pterosaurs. Not only is it factually correct, it also opens doors to more curiosity. Why do they say pterosaurs instead of dinosaurs? Turns out they are separate clades. The pterosaurs, plesiosaurs and mosasaurs are all extinct as best as we can tell. The dinosaurs are not.

    • bregma 7 days ago |
      Dinosaurs are delicious. They taste like chicken.
      • pier25 7 days ago |
        Proof we live in a simulation. Everything tastes like chicken!
    • jvanderbot 7 days ago |
      This is fascinating. Although I'm having trouble mapping your comment onto this: https://opengeology.org/historicalgeology/case-studies/dinos...

      What is the complete set and which are extinct?

      • addaon 7 days ago |
        > What is the complete set and which are extinct?

        That's as good a complete tree as you're likely to get, down to the class level. Some species in the class Aves survived, and progenitor species with Aves are still around today. There's no significant evidence of species in other classes of the clade Dinosauria surviving much past the impact boundary.

        You can push this up one level to the clade Avemetatarsalia (including Pterosaurs along with Dinosaurs) and the statement above would still be true; but pushing it further to Archosauria would not be valid, because crocodilians survived (and survive) as well.

      • Timwi 5 days ago |
        The diagram in your link only shows the dinosaurs, not the entire tree of animals alive at the time. Within that diagram, everything except Aves (which, incidentally, is the Latin word for birds) is believed to be extinct.

        The article makes no mention of other clades that lived during the Cretaceous, such as the pterosaurs, or indeed the mammals. Just as birds are descendants of the few surviving dinosaurs, we are descendants of the few surviving mammals.