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...
> 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:
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.
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.
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.
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.
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.
The paper is at https://www.pnas.org/doi/10.1073/pnas.2408721121. We've adopted its title above.
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...
Here is the Chixculub impact effect in realtime simulated as happening in today's world: https://youtu.be/ya3w1bvaxaQ?si=S-jmFegMo63HKzID
> 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
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...
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.
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.
https://www.google.com/search?q=bike+shedding
When referring to dinosaurs, most people are thinking about non-avian, teethed dinosaurs anyway.
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.
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?
Dinosaurs are delicious. They taste like chicken.
Proof we live in a simulation. Everything tastes like chicken!
Vote for Giant Meteor 2028!
https://votegiantmeteor.com/
When is the next one coming? Or what is the probability distributuon like?
It's a poisson distribution.
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.
Likely it isn't, because the Solar system today and 3Bln years ago are two very different systems.
Have the data actually been fit a Poisson distribution? Or is this is just a guess assuming constant rate and independence?
No natural phenomena ever exactly fits any probability distribution.
Right but I'm saying do we have data showing it's even close? (Genuinely asking, I have no idea.)
except the emission spectra from atoms :)
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.
Likely due to this: https://en.wikipedia.org/wiki/Late_Heavy_Bombardment
What these authors claimed recently was that prior LHB estimates were low by a large factor. https://www.nature.com/articles/s41561-021-00835-9
Thanks for the paper link!