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Effect of a giant meteorite impact on Paleoarchean environment and life

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Re: Effect of a giant meteorite impact on Paleoarchean environment and life

#31

Post by chiefalchemist »

kevinkeller wrote: post #6

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_crate…

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...

Re: Effect of a giant meteorite impact on Paleoarchean environment and life

#32

Post by defrost »

iambateman wrote: post #29
bulatb wrote: post #27

Earlier quoted context omitted.

Skepticism should begin with the skeptic's own motives. A skeptic's second question (after "Really?" or "Why?") should be, "Why am I asking?" Do they want to test the claim to learn something, or to dismiss it, just to dismiss it? If they're asking questions which are literally answered as part of the claim, they need to start over, and start with themselves.

The article claims that 363 billion tons of phosphorous were dropped on earth 3.26 billion years ago during a decade of darkness. I’m completely incapable of making sense of that claim because it’s so far outside of my expertise. But my fundamental problem is that I don’t trust the source’s incentives to deliver reliable information and I want someone independent to help me understand if this is a how strong or weak…

There's no one stop shop for instantly correct science, think less about retractions and more about incremental advances toward better understanding.

> The article claims that 363 billion tons of phosphorous were dropped on earth 3.26 billion years ago

The article correctly reports that a series of papers claim that a bolide (large mass) of an estimated diameter of 37 to 58 km across impacted some time ago.

There's a slew of paths forward for anyone interested in knowing more and questioning these claims.

The 96 references cover such things as estimating the impact crater, spray field, and impactor size.

You might want estimate for yourself the mass of a spherical cow some 40km in diameter if the material were to be (say) nickel iron .. and then perhaps back of the envelope determine what fraction of that would 363 billion tonne be.

It may or may not help to know that W.Australia move a billion tonne of iron ore per annum, that's a certain volume of mesa uprooted and moved to China, and 363 years of that would be a similar mass and volume.

This goes to having a feel for the paper's methodology in estimating P mass.

You may also wish to review papers and books on the K-Pg bolide, the one that "killed the dinosaurs" which is estimated to be some ~50 to 200 times smaller by mass than the one discussed here.

There's also a body of work on theories of planet formation via big rocks smashing into each other, sticking together, and planets slowing growing as stray rocks get hoovered up.

Re: Effect of a giant meteorite impact on Paleoarchean environment and life

#33

Post by EGreg »

drdaeman wrote: post #22
EGreg wrote: post #12

Earlier quoted context omitted.

[flagged]

I hope that your reaction is because the headline is way more sensational (to the extent of probably being incorrect) than the actual paper's abstract ( https://www.pnas.org/doi/10.1073/pnas.2408721121 ) Here's what the actual paper says: > [...] Thus, the S2 impact likely had regional, if not global, positive and negative effects on life. The tsunami, atmospheric heating, and darkness would likely have decimated pho…

[flagged]

Re: Effect of a giant meteorite impact on Paleoarchean environment and life

#34

Post by aspenmayer »

bulatb wrote: post #27
iambateman wrote: post #15

Earlier quoted context omitted.

The downvotes are misplaced. This is a good question. The value of HN is when people-who-know help curious folks understand the validity of a story. Surely someone here is more capable of assessing this story and I agree that skepticism is in order at first.

Skepticism should begin with the skeptic's own motives. A skeptic's second question (after "Really?" or "Why?") should be, "Why am I asking?" Do they want to test the claim to learn something, or to dismiss it, just to dismiss it? If they're asking questions which are literally answered as part of the claim, they need to start over, and start with themselves.

> Sealioning (also sea-lioning and sea lioning) is a type of trolling or harassment that consists of pursuing people with relentless requests for evidence, often tangential or previously addressed, while maintaining a pretense of civility and sincerity ("I'm just trying to have a debate"), and feigning ignorance of the subject matter. It may take the form of "incessant, bad-faith invitations to engage in debate", and has been likened to a denial-of-service attack targeted at human beings. The term originated with a 2014 strip of the webcomic Wondermark by David Malki, which The Independent called "the most apt description of Twitter you'll ever see".

https://en.wikipedia.org/wiki/Sealioning

The comic strip in question is actually adorably absurd:

http://wondermark.com/1k62/

Re: Effect of a giant meteorite impact on Paleoarchean environment and life

#35

Post by Q_is_4_Quantum »

glial wrote: post #28
dataflow wrote: post #25

Earlier quoted context omitted.

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.

except the emission spectra from atoms :)

Re: Effect of a giant meteorite impact on Paleoarchean environment and life

#36

Post by dan353hehe »

aspenmayer wrote: post #34
bulatb wrote: post #27

Earlier quoted context omitted.

Skepticism should begin with the skeptic's own motives. A skeptic's second question (after "Really?" or "Why?") should be, "Why am I asking?" Do they want to test the claim to learn something, or to dismiss it, just to dismiss it? If they're asking questions which are literally answered as part of the claim, they need to start over, and start with themselves.

> Sealioning (also sea-lioning and sea lioning) is a type of trolling or harassment that consists of pursuing people with relentless requests for evidence, often tangential or previously addressed, while maintaining a pretense of civility and sincerity ("I'm just trying to have a debate"), and feigning ignorance of the subject matter. It may take the form of "incessant, bad-faith invitations to engage in debate", and…

Thank you!

I have been trying to remember the name for that comic for years, and no amount of searching has ever yielded anything.

Re: Effect of a giant meteorite impact on Paleoarchean environment and life

#37

Post by aspenmayer »

dan353hehe wrote: post #36
aspenmayer wrote: post #34

Earlier quoted context omitted.

> Sealioning (also sea-lioning and sea lioning) is a type of trolling or harassment that consists of pursuing people with relentless requests for evidence, often tangential or previously addressed, while maintaining a pretense of civility and sincerity ("I'm just trying to have a debate"), and feigning ignorance of the subject matter. It may take the form of "incessant, bad-faith invitations to engage in debate", and…

Thank you! I have been trying to remember the name for that comic for years, and no amount of searching has ever yielded anything.

Aww! I love that for you. Finding things people are searching for is a bit of a hobby of mine, so I’m happy I was able to have helped you.

Re: Effect of a giant meteorite impact on Paleoarchean environment and life

#38

Post by rcyeh »

iambateman wrote: post #29
bulatb wrote: post #27

Earlier quoted context omitted.

Skepticism should begin with the skeptic's own motives. A skeptic's second question (after "Really?" or "Why?") should be, "Why am I asking?" Do they want to test the claim to learn something, or to dismiss it, just to dismiss it? If they're asking questions which are literally answered as part of the claim, they need to start over, and start with themselves.

The article claims that 363 billion tons of phosphorous were dropped on earth 3.26 billion years ago during a decade of darkness. I’m completely incapable of making sense of that claim because it’s so far outside of my expertise. But my fundamental problem is that I don’t trust the source’s incentives to deliver reliable information and I want someone independent to help me understand if this is a how strong or weak…

Just going through the numbers:

363 BB tons / (1 ton / cu m) / (1 BB cu m / cu km) is the mass of a 9-km-diameter ice ball, smaller for rockier materials.

363 BB tons / 10 years = 100 MM tons / day.

By comparison, Mount St Helens (1980) and Eyjafjallajökull (2010) each produced 500 MM tons of ash. So the amount of material is about equivalent to having a similarly-sized volcano eruption every few days for ten years straight.

The Earth's surface area is 500 MM sq km. If we were to distribute 363 BB tons uniformly, that would be an average of 1000 tons per sq km. If the layer had a density of 1 ton per cu m (same as water), the resulting layer would be 1/1000 of a meter thick. This seems to be thinner than the spherule layers described.

Re: Effect of a giant meteorite impact on Paleoarchean environment and life

#39

Post by dang »

EGreg wrote: post #33
drdaeman wrote: post #22

Earlier quoted context omitted.

I hope that your reaction is because the headline is way more sensational (to the extent of probably being incorrect) than the actual paper's abstract ( https://www.pnas.org/doi/10.1073/pnas.2408721121 ) Here's what the actual paper says: > [...] Thus, the S2 impact likely had regional, if not global, positive and negative effects on life. The tsunami, atmospheric heating, and darkness would likely have decimated pho…

[flagged]

Please don't take the bait. It's fine to let us know when a headline is sensational/distorted so we can change it. It's not fine to take to the comments about it, because that is likely to produce a shallow and less interesting discussion, which is what happened here.

Edit: I've changed the title to that of the paper.

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