The dying of the dinosaurs
In the comments to yesterday’s post about climate change, a lot of people mentioned this article that appeared in The New Yorker and caused a big sensation.
I had already read the article and found it to be absorbing. It helps that the author of the piece is a novelist, because not only did the article zip right along, but it read almost like a short story, a very dramatic one. The picture it created of the aftereffects of the asteroid hit that is presumed to have ended the dominance of the dinosaurs as a group and paved the way for mammals to rise was both fascinating and terrifying:
Within two minutes of slamming into Earth, the asteroid, which was at least six miles wide, had gouged a crater about eighteen miles deep and lofted twenty-five trillion metric tons of debris into the atmosphere. Picture the splash of a pebble falling into pond water, but on a planetary scale. When Earth’s crust rebounded, a peak higher than Mt. Everest briefly rose up. The energy released was more than that of a billion Hiroshima bombs, but the blast looked nothing like a nuclear explosion, with its signature mushroom cloud. Instead, the initial blowout formed a “rooster tail,” a gigantic jet of molten material, which exited the atmosphere, some of it fanning out over North America. Much of the material was several times hotter than the surface of the sun, and it set fire to everything within a thousand miles. In addition, an inverted cone of liquefied, superheated rock rose, spread outward as countless red-hot blobs of glass, called tektites, and blanketed the Western Hemisphere.
Some of the ejecta escaped Earth’s gravitational pull and went into irregular orbits around the sun. Over millions of years, bits of it found their way to other planets and moons in the solar system…
There’s much much more, but you get the idea.
The description of the discoverer of the fossil find that supposedly documents this event is fascinating as well. He appears to be monomaniacal about bones and how they fit together; obsessed with them from around the age of four, helped along by a great-uncle who was a renowned orthopedist.
“We have the whole KT event preserved in these sediments,” DePalma said. “With this deposit, we can chart what happened the day the Cretaceous died.” No paleontological site remotely like it had ever been found, and, if DePalma’s hypothesis proves correct, the scientific value of the site will be immense. When Walter Alvarez visited the dig last summer, he was astounded. “It is truly a magnificent site,” he wrote to me, adding that it’s “surely one of the best sites ever found for telling just what happened on the day of the impact.”
As I read the article, though, one thing that struck me was this question: hasn’t earth a lot of impact craters from fairly large asteroids? Did they cause similar extinctions? Was this the largest asteroid ever? The extent of the cataclysm described in the article is based on computer modelings, but how accurate are those modelings?
The following was in the article as well:
Scientists still debate many of the details, which are derived from the computer models, and from field studies of the debris layer, knowledge of extinction rates, fossils and microfossils, and many other clues. But the over-all view is consistently grim. The dust and soot from the impact and the conflagrations prevented all sunlight from reaching the planet’s surface for months. Photosynthesis all but stopped, killing most of the plant life, extinguishing the phytoplankton in the oceans, and causing the amount of oxygen in the atmosphere to plummet. After the fires died down, Earth plunged into a period of cold, perhaps even a deep freeze. Earth’s two essential food chains, in the sea and on land, collapsed. About seventy-five per cent of all species went extinct. More than 99.9999 per cent of all living organisms on Earth died, and the carbon cycle came to a halt.
Earth itself became toxic. When the asteroid struck, it vaporized layers of limestone, releasing into the atmosphere a trillion tons of carbon dioxide, ten billion tons of methane, and a billion tons of carbon monoxide; all three are powerful greenhouse gases. The impact also vaporized anhydrite rock, which blasted ten trillion tons of sulfur compounds aloft. The sulfur combined with water to form sulfuric acid, which then fell as an acid rain that may have been potent enough to strip the leaves from any surviving plants and to leach the nutrients from the soil.
So how did the mammals survive? What did they eat, for example? I’d like to know a lot more about that.
Would a similar-sized impact always and inevitably have a similarly horrific result? Haven’t many asteroids hit earth, and were some of them almost as big? I found this article that goes into the question a bit, enough for me to conclude that we aren’t entirely sure how big the Chicxulub crater (the impact described in the New Yorker article) actually is, although it’s certainly very very big. But I noticed that about five million years prior to Chicxulub, there had been another large impact (called the Kara crater) that doesn’t seem associated with any mass extinction (at least, I couldn’t find any discussion of it in a brief perusal). If not, then why?
I certainly don’t know. But I found an article from 2017 that raises some interesting points:
Of all the places in the world an asteroid could have walloped ancient Earth, the Yucatán Peninsula was possibly the worst…
According to the paper, this mass extinction happened because the space rock slammed into an oily tinderbox, blasting enough soot into the atmosphere to cause extreme global cooling…
The impact chilled the planet by a global average of 14 to 18 degrees Fahrenheit, with a drop of 18 to 29 degrees over land, the study finds.
Only 13 percent of Earth’s surface is made up of rocks that could have burned off that much soot, the team argues this week in Scientific Reports. That means if the asteroid had landed almost anywhere else, the nonavian dinosaurs may not have died out after all.
“This is a fascinating paper that … argues that even given the large size of the impactor, the mass extinction itself was of low probability,” says Paul Chodas, manager of the Center for Near Earth Object Studies at NASA’s Jet Propulsion Laboratory.
The possibility of a catastrophic asteroid impact is the meat-and-potatoes of many science fiction stories and films. Often they feature humankind attempting to head the asteroid off at the pass, and in real life we do have some rudimentary efforts to move in that direction:
In 2016 a NASA scientist warned that the Earth is unprepared for such an event. In April 2018, the B612 Foundation reported “It’s 100 per cent certain we’ll be hit [by a devastating asteroid], but we’re not 100 per cent sure when.” Also in 2018, physicist Stephen Hawking, in his final book Brief Answers to the Big Questions, considered an asteroid collision to be the biggest threat to the planet.[4][5][6] In March 2019, scientists reported that asteroids may be much more difficult to destroy than thought earlier. In addition, an asteroid may reassemble itself due to gravity after being disrupted.
If you’re interested in some of the contemplated approaches, see this. Suffice to say that our skills in this direction are in their infancy.
[NOTE: Here’s a database of known impact events.]
All those craters on the moon are evidence of impacts. I think I read somewhere that the moon catches a lot of asteroids on their way to us.
There’s an excellent documentary about Eugene Shoemaker’s quest to convince the community of geologists that major meteorite impacts were relatively common on earth.
Asteroids: Deadly Impact
“After studying craters produced by atomic bomb tests, Gene realized, contrary to current geological thought, that the Earth has been bombarded in the past by large objects from space.”
Seems weird in hindsight because the earth has a prodigious rate of surface erosion, which explains why most surface craters don’t last.
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If the Chicxulub impact was near the equator then as it is now, the spin of the earth would have wrapped the devastation around the globe. The Kara crater, is now above the artic circle which would help keep the devastation within the artic region.
It always struck me that schemes to deflect an incoming asteroid in the future were smarter than schemes to destroy it. But then one needs to detect it many months in advance. An interesting part of the problem is that our telescopes are blind to certain parts of the sky (sunward looking?) and there is a possible plan for a space telescope that would orbit the sun in the earth’s path, but separated from earth by months worth of orbit time.
The biggest earth impact, if the theory is correct, was the one that created a “rooster tail” so big that a giant molten glob broke off and became the moon. It was long before there was life of course. I’ve seen (somewhere) a nifty computer simulation of the hypothetical event.
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The “rare earth” theory is that there are many things about our solar system that are relatively or highly unique compared to the “average” solar system. Not that we have a really good idea what the average one is.
A possibly rare characteristic is that we have two gas giants, Saturn and Jupiter, located in the middle of the planetary plane, and their orbits are phase locked. This purportedly has the gravitational effect of sweeping out most of the asteroids from the path of the planets, and I guess confining them within a belt. This would argue that most of those craters on the moon were created at a much earlier time in our solar system’s evolution.
Like you, I was captivated by this article, especially the description of DePalma.
RE: “So how did the mammals survive? What did they eat, for example?”
What do mammals do when winter comes? Many have stockpiled food, but the great thing about being a mammal is being able to curl up and wait out the cold. As long as they aren’t having to move around, their nutritional needs are low. Reptiles that I’ve seen need the warmth of the sun to keep their body temperature up. I would imagine that after a few weeks of cold, something that the dinosaurs may not have been equipped to handle, they’d just die. Then, many of the rat-like mammals would have had plenty to eat.
“So how did the mammals survive? What did they eat, for example?”
A good question. Some could have hibernated, I suppose… but hibernation tends to be a rhythmic thing, something that mammals do at a specific time of year. And not all mammals hibernate. Birds have it even worse – and there were plenty of birds around, many of which survived the extinction. Even more interesting, a study about twenty years ago showed that for lower tetrapods (amphibians and reptiles), there was _no_ mass extinction at the K-T boundary. Every non-avian dinosaur died, every large marine reptile died, every enantiornithine bird died, every remaining ammonite died — the selectivity of the extinction event is quite impressive, and inconsistent with the ‘Asteroid Doomsday’ sweeping-mass-death scenario.
Such questions, to which the Asteroid Doomsday proponents have no good answers, are a big reason why many people think the Asteroid Doomsday hypothesis is flawed. That there was an impact seems beyond a reasonable doubt; that it caused the extinction is not.
kevino:
Actually, it seems that the mammals who survived were mainly insect eaters.
But with no plants, what did the insects eat? Carrion? Later on I’ll look to see if there are any articles about that.
Seeds pack nutritional punch and can last long in some cases. On another hand, perhaps some mammals ate other mammals (after all, we do).
Would a similar-sized impact always and inevitably have a similarly horrific result? Haven’t many asteroids hit earth, and were some of them almost as big? –neo
neo: That’s a fascinating bit about the oily rock ignited by the KT asteroid. Could be.
However, there have been massive asteroids or worse hitting the earth. The current theory of the moon’s formation is that an object the size of Mars hit the Earth very early on and our Moon is a combination of that object and parts of the Earth ejected from the collision.
Single-cell life started very early too and may or may not have been around for that collision. However, single-cell life is fantastically resilient, e.g. the so-called “extremophiles,” so that life wouldn’t blink short of something which would burn the Earth to a cinder. Maybe not even then.
Over time, however, the solar system settled down. There are fewer random objects flying around hitting the Earth. TommyJay points out the theory that Saturn and Jupiter vacuum up a lot of the nasty stuff up so it doesn’t hit the Earth.
The Earth is roughly 4.5 billion years old. The Cambrian Explosion in which multicellular life emerged was only half-billion years ago, followed by plants, insects and fish. The vertebrates we think of as life — proto-reptiles, proto-mammals — started appearing ~250 million years ago.
The point being that what we think of as life only happened in the most recent ~4% of the Earth’s age and over time there are fewer, smaller objects to hit the Earth.
Which is not an argument for complacency, just perspective. I think it would be hard to kill off homo sapiens, but human civilization is far more fragile.
Cormac McCarthy wrote a thoroughly grim, post-apocalyptic, Pulitzer Prize winning novel titled “The Road,” later made into a thoroughly grim, post-apocalyptic movie starring Viggo Mortensen.
McCarthy didn’t explain the apocalypse which caused that future, but his inspiration came from a science lecture at the Sante Fe Institute about the repercussions of a mass extinction event caused by a massive comet or asteroid hitting the earth in the modern world.
The film is worth watching but make sure you have something lively and fun to do afterward.
neo:
RE: “Actually, it seems that the mammals who survived were mainly insect eaters. But with no plants, what did the insects eat? Carrion?”
Very interesting. I’ll have to read that in more detail. Off the top of my head:
(1) “Mainly insect eaters” doesn’t say “exclusively insect eaters”.
(2) Obviously, plants made a come-back.
(3) Early mammals may have been able to adapt to the extraordinary circumstances at hand. If they were hungry enough, those that scavenged survived easily.
(4) The description of the rat-like tritheledonts would appear to be able to make this adaptation easily.
(5) I really like your idea that the insects would survive — and I’m sure that they would. And then there is plenty of food for the early mammals. Interesting.
(6) All of this is based on fossil records, and those records have gaps. (The article itself is about a find that fills in a gap.) We may know more when DePalma publishes his next paper.
Look up who created the whole dinosaur theory to begin with.
neo:
Your theory has substantial support: “Following the asteroid hit, most of the plants and animals would have died, so the survivors probably fed on insects eating dead plants and animals. With so little food, only small species survived. The biggest animals to survive on land would have been no larger than a cat. The fact that that most mammals were small helps explain why they were able to survive.”
source: https://phys.org/news/2016-06-mammals-dinosaurs.html
see also: https://www.quora.com/How-did-all-the-dinosaurs-die-but-plants-insects-and-mammals-live
As long as there is some sunlight and some organic matter around, there will be stuff for the little things to eat and little things for the bigger things to eat, etc.
It won’t be Club Med or haute cuisine, but life goes on, however reduced in size and numbers.
A friend and I used to compete on the question “How could the human race be killed off?” (OK. We are sick people.)
Short of something cosmic like a gamma-ray burster exploding nearby which would incinerate the earth, we couldn’t come up with a solution.
It’s easy enough to kill almost everyone, but nuclear weapons, plagues, eco-catastrophe and whatnot just won’t finish the job. There will always be someone in a mine shaft or at the poles or willing to live miserably but just long enough to reproduce that the human race will survive.
Huxley, what of the small population bottleneck problem? I seem to recall vaguely a suggestion (theory?) that the homo sapiens were a touch and go proposition at one early date on account of the super volcano Toba, escaping only by the skin of their teeth, so to speak. Anyhow, numbers and variety within those numbers appear to count for something important in some circumstances.
sdferr: That was 70,000 years ago when our tech wasn’t quite so good and we didn’t have several billion people to spare.
A friend and I used to compete on the question “How could the human race be killed off?” (OK. We are sick people.)
Oh that is pretty easy. We just have to hit the server reset button. Or transmigrate the servers and force fields around the Earth.
As for asteroids, if these things actually existed, one would get more than just a 90 degree crater. We would get those long furrows like a plane crashing down. The moon and mars just look like a shotgun hit it at 90 degrees, right on, such as WMD or some type of event science tries to put labels on like religion does with Eden and sin.
Eve was deceived and caused Adam to sin!
An asteroid hit the Earth! Meteorites hit the moon!
Maybe the weird craters are eroded on Earth due to water, but what about the moon. Where are the streaks 90 miles wide of something hitting at an angle and driving a plow through the lunar surface? It’s all a circular crater. That is what happens when you drop a WMD kinetic strike on something directly.
If you humans want to see the divine power, just keep killing babies, eating them, cutting sexual organs off of 7 year olds, and you will see personally what happened to Soddom and Gomorrah.
Looney tunes.
The New Yorker essay is a welcome change from their usual fare, but when a writer’s vivid imagination is combined with computer simulations, the result can skate the thin edge of fiction. Lots of speculation, but not necessarily wrong.
I don’t want to pick apart the New Yorker essay, and it’s silly to minimize one of the world’s worst cataclysms, but the work done by DePalma and colleagues takes a decidedly different tone in their own paper. For anybody else who wants to read it, here’s a link: https://www.pnas.org/content/early/2019/03/27/1817407116
Huxley:
It’s all explained in “We’re All Bozos on this Bus” by Firesign Theatre, events that happened after the “Late Devouring Period.”
Takin’ it with a grain of salt.
Deconstructing a Chicxulub Crater/Extinction, in 5 easy pieces
1.) If the Iridium does not fit, you must acquit! Closer, more-local deposits do not reflect a heightened level of iridium, as would be expected if this site was ground-zero for a global iridium-enrichment event. More generally, accounting for the diffuse distribution (er, ‘non-pattern’) of this element in the very widespread KT horizon (aka, ‘iridium enriched layer’), is itself a tough scientific problem. Thus, the original ‘Ah-ha!’ datum could itself turn out to be the fatal ‘oopsie’ of this Theory… because the more-finely we fill-in the spacial data-points for this mysterious horizon-artifact, the more problematic it becomes to explain it as having originated from a – ‘any’ – single location.
2.) Crater? What crater? The crater-images per se are a Rorschach Test, and that’s being generous. On the land, a loose association between blotchy features said to represent the curve of part of a crater-rim, with a roughly-parallel distribution of sink-holes on the Yucatan Peninsula, is held up as a ‘See?!’. Pragmatically, nothing is offered to support the suggestion that the sink-holes have any bearing on whether the vague partial-ring is a crater rim, or not. In fact, if it were not for the sink-hole sites ‘reinforcing’ the image of the partial-ring, (which are commonly ‘Photoshop-assisted’ … since actually they are totally invisible, relative to the putative rim-feature), a prudent reader-observe would typically respond, “What crater? I don’t see no crater”. That’s really why we have the cenote/sink-hole sites are in the script … and ‘visually enhanced’. In court, this is ‘Leading the witness’.
3.) Beneath the deep blue briney. At sea, the crater-rim ‘signal’ virtually disappears. Yet arguably features on the continental shelf that are submerged should be better-preserved, being protected from weathering. Admittedly, the surface-component of any crater-feature (from an impact of this magnitude) will be a small component of the overall structure of the (many miles deep) scar. But gravimetric readings, which underpin the land-based images, should work just fine to reveal a submarine continuation of the rim-circle … and the fact that they don’t is glossed-over.
4.) Drill here! Drill now! A model was developed to predict what the subterranean materials under the impact-site would be & look like. Then they drilled … and probably wished they hadn’t. What came up in the cores did not match the model, and worse does not fit with a ‘stupendous’ melt-event. It looks more like typical busted-up stuff that is commonly encounter in geology, and which we normally explain in terms of a dozen different but entirely-terrestrial dynamics. Admittedly, drilling could not reach very far at all, into a big impact-signature … but it was their idea!
5.) LANL Los Alamos National Laboratory has been on the case for a long time. They started with Tunguska, back before a string of science-breakthroughs & contemporary impacts (but after satellites had established an anomalous pattern of suspicious & foreboding upper-atmosphere infrared events) redefined our ideas about how these strikes work. With their supercomputer simulation, they depicted a high-energy atmospheric event, but deviated from orthodoxy by optionally ascribing it to an undersized solid object. Atmospheric release was ok, for a ‘snowball’, but not for big rocks. At first, they got the brush-off, but later events (Chelyabinsk) raised their profile, and ‘take’.
LANL sez you have to keep 2 things in mind, with any Chicxulub impact.
a.) It matters whether it was a comet or an asteroid.
b.) It matters at what angle it came in at.
A comet is of lower density, but has more kinetic energy because it is going much faster after falling further toward the sun.
Ocean-impacts are different. Possibly MUCH different. We remain in fumble-mode, with respect to deep-ocean impacts. The Chicxulub site, however, is (was) shallow-ocean continental shelf, 900 to 1,000′ feet deep. The question with this site becomes: What might have been the role & effect of a potentially 1,000′ wall of (ocean) water, plunging into (or more like, ‘toward’) a white-hot hole or caldera, 10s of miles across? Or did a newly-raised rim hold the ocean out?
If the object was mainly water (comet), then the role of water-vapor amplifies even-more dramatically. With the involvement of large or larger amounts of water, there is the potential for an in-sucking hurricane-like dynamic, as cubic miles of water-vapor condense & deluge back to earth … potentially washing a lot of the solid debris out, closer/near to the site, instead of it spreading-out, circling the earth.
Condensation effects that draw-in and wash-out the debris increase the likelihood of survivable refugia.
All impact-events have an entry-angle, and in the case of Big impacts, how they affect the planet depends a good deal on the angle of the strike. General remarks about the lofting, movement & circulation of debris, in the case of an impact of this putative size, very much rely on the angle … which is rarely acknowledged, because the offered depiction is very much dependent on (varies with) that angle, the importance of which is being fudged. And the fudgers are perfectly aware of this.
LANL seems to be a ‘well-behaved’ critic/skeptic (there are (always have been) other academic impact-skeptics who range across a spectrum of couthness). It would probably not hurt LANL’s feelings if someone/something else disproves the Chicxulub impact and/or extinction effect.
Before Luis Alvarez and his discovery of the enriched-iridium-layer, science had long speculated about the possible ways in which the dinosaurs might have died-out. The KT iridium-layer is an objective discovery, but the interpretation of it as ‘proof’ of an astronomical impact, seems like a scientific stretch. The attractive thing about the old ideas (disease, genetics, volcanos, etc), is that they resisted the impulse to ‘bet the farm’ that this or that speculation was for-sure the one-and-only possible explanation. Luis cast the old caution to the wind … as had Margaret Mead.
Both Luis and Margaret reflect the move to Big Idea science (a social effect of TV?). Wade ashore on scant objective evidence & grandly claim all the lands washed by this sea, in the name of one’s Kingly notion. If defects & gaps remain, let the lesser intellects struggle to patch ‘n plug ’em.
My Big Idea is that this is a disease of the Institution of Science, and epidemiology will eventually name it.
Ted Clayton: Thanks for a great comment!
But in little words … you are saying … the science is not settled and we should not trust this article’s narrative just yet?
“1) If the Iridium does not fit, you must acquit!”
Very funny! I had to read it about 3 times to get the point, I think. So the spatial distributions of iridium don’t work out compared to the theory of a Chicxulub impact?
Is there an alternative theory that does explain the measured iridium?
I’d never thought about a comet comprised of frozen water and gases in this context. Can you say phase-change?
I had the same problems with the “TOTAL WIPEOUT OF EVERYTHING EVERYWHERE FOR A LONG LONG TIME” take of the article and the obsessed man portrayed.
It got my attention but, since that central assertion of total wipeout was not addressed I ended up thinking as I often do and have for a number of years, “Wow, you just can’t trust or believe The New Yorker anymore. Yes, The New Yorker.”
Sad. It was once a great magazine.
I had the same problems with the “TOTAL WIPEOUT OF EVERYTHING EVERYWHERE FOR A LONG LONG TIME” take of the article and the obsessed man portrayed.
Gerard vanderleun: DePalma’s site may not provide the serendipitous slice of time within hours of the KT boundary, but something serious happened around then and the dinos died off as well as much other life, though not totally.
Or have you become a Young-Earth Creationist or something? Not that there is anything wrong with that…
Wow, Ted Clayton, thanks very much for your enlightening comment. I don’t have the training to read anywhere near that critically. I’m guessing that maybe the takeaway is huxley’s comment: “the science is not settled and we should not trust this article’s narrative just yet?”
Still, it makes a heck of a good story.
Interesting comments. I guess the “science is not settled,” at least not just yet. But I’m sure that President Light-Bringer could settle it for us. After all, when at Harvard Law, I believe he wrote some Sokal-like material on science in collaboration with Prof Laurence Tribe. 🙂
I better start reading The New Yorker article.
Big problem, we can not know what is what if didn’t we observe it first hand or it is reliably documented. Beyond that is merely superstion and speculation. We just don’t know. Get used to it. You don’t know turtels upon turtels. You don’tknow.
Thanks for the nice feedback, guys!
The original paper on PNAS (about the “Tanis” paleontology site, in the Hell Creek Formation, North Dakota): A seismically induced onshore surge deposit at the KPg boundary, North Dakota
<Huxley, I too see it as unsettled science. And as two different science-questions. That the dino-demise occured across millions of years is stongly-enough supported by paleontology that serious Chicxulub people have crafted an alternative, in which fragments of the original impactor hit us repeatedly, eventually compromising different parts of Earth.
<TommyJay, a main alternative source of iridium is heightened periods of vulcanism or geologic activity. Vigorous spreading along the centers of the oceanic plate-seams could release vast amounts of precipitates accumulated along the cracks. The KT boundary layer itself is quite odd, not like material from a colossal explosion. And in keeping with Neo’s observation about the dirth of impact-features, there is simply no other sedimentary artifact comparable to this iridium-enriched-layer.
Yes <Mrs Whatsit, it is a Good Story, and there is no reason why science shouldn’t have them. Of course, it’s incumbent on all to let others buff their own stories … and that’s the rub. That the iridium could only have come from an asteroid (which might have been a comet instead, and then would have had no where near as much/enough), runs up against the standard planetary creation process, which says the earth was built-up from asteroidal/planetesimal material … and should have the same iridium as remaining left-over asteroids. Like other heavy stuff, it’s mostly worked it’s way down deeper.
If I recall correctly from Niven and Pournelle’s Lucifer’s Hammer, it makes a great deal of difference whether the asteroid hits land or water. I’ll have to read that again – it’s been 40 years.
Wait. So Trump is really some kind of asteroid?????
As more and more scientific evidence—from genetic research, from paleontology, from geological and archeological studies accumulate—it is being revealed that, throughout our history, the human race has been far more subject to violent natural catastrophes than we might have believed it to be.
It is starting to appear that the Earth (and, more recently, the human race) has been the recipient and victim of far more violent and catastrophic natural events than we have been aware of.
To take just one category of such events, there are strikes by asteroids and all their subsequent results—world covering debris clouds lofted into the atmosphere, massive fires, tsunamis and floods, volcanic eruptions, earthquakes, associated lava flows and poison gasses released into the atmosphere, increased or decreased temperatures, glaciation, and the resultant prolonged years of cloud cover that killed off plants and thus animals, all resulting in massive, almost complete, world-wide die offs of both plants and animals.
These wide-ranging, catastrophic events have apparently had far more of a determinative effect on the rise and progress of humankind than has been commonly acknowledged and understood.
Just to take two examples, there are DePalma’s new KT boundary discoveries about the catastrophic impact of the Chicxulub asteroid strike, some 66 million years ago, and also the recently discovered meteor strike of about twelve thousand nine hundred and fifty years ago that also resulted in massive die offs.
The Universe is, it appears, a far more dangerous a place than we realized, one that is far more often, and far more randomly violent than most of us have generally given it credit for and, thus—as more and more evidence accumulates about just how many repeated catastrophic events the Earth has been subjected to—it makes it clearer and clearer that humankind’s position here on Earth is far more vulnerable and precarious than we realize.
One indication of catastrophic natural events effects on the human race are the “population bottlenecks” that genetic researchers now believe took place—likely on several different occasions in human history—in which the entire human breeding population might have been reduced to just several thousand, or even several hundred individuals or less.
Our vulnerability here on Earth is something to pay close attention to, to acknowledge on a fundamental level, and to urgently try to fix.
Thus, my comment on this site a week or two ago about how imperative it is for us to get one or more human breeding populations off this planet, and situated in other, hopefully more secure locations in our Solar system, before some other meteorite comes along to smash into our planet, or some other major natural, or human-generated catastrophe occurs.
Not an easy task to accomplish but, nonetheless, Imperative.
Notes on DePalma et al, PNAS, April 1 2019
This is a quick first-glance, hitting a few selected key matters. I have a big pick & shovel, waterline workday today, and will be offline.
1.) Densely packed fish. This feature of the deposit is accounted for as part of a “high energy” event. Generally though, a mass of fish-carcasses tightly packed together represents & is accounted for as any of a range of characteristically low energy events/contexts. Fish get trapped in a pool that dries-out. They are killed some other way, then are gently eddied or windrowed into a packed-mass. A violent wave, on the other hand, scatters & disperses ‘everything’. The authors are swimming upstream, bucking the normal explanations for the observed deposit … which is that a low-energy situation allowed the mass to form.
2.) It was not a Tsunami! The Abstract states, “Although this deposit displays all the physical characteristics of a tsunami runup…, we’re going to ignore the obvious and instead explain it in terms of a much less likely process. In order to tie it to Chicxulub! This appears to be ordinary confirmation-bias in-action, and it runs from beginning to end. But tsunami-type and other burial-mechanisms are the much more common, straight-forward way to account for desposits such as this. But then, it wouldn’t be Chicxulub.
3.) Microspherules as impact-evidence. Actually, tiny little round things “grow” in the ground, in various sorts of depositional contexts. They are also created by lightning, and by big & little meteors. In the same way and for the same underlying reasons that foams & bubbles form into spheres, and that the basic shape of primitive Cellular Life is a round ball, low-level geochemical processes form “concretion objects”, as little spheres. Again, it’s a case of avoiding the obvious, or transmuting the mundane into something very unusual.
4.) End-stage isolation of Iridium The Platinum-group elements, termed PGEs here & elsewhere, are reluctant to combine with other elements. Therefore they tend to be found in the last stages of mineral-differentiation sequences, and ‘trapped’ in concretion-structures that contain the stuff that didn’t want to combine with anything else. Instead of going out and making an effort to determine the base-line dynamics & roles of microspherule formation in general, in normal geological contexts, several active ‘camps’ are studiously ignoring evidence that these little objects form by both mundane processes, and under other unusual or weird situations … so they can claim that they represent Astronomical Impacts.
In the end, most investigative avenues that currently rely on microspherules will require a climb-down.
The dating is interesting, as is the 3.8 ppb iridium-level that is reported. Time to go.
Snow On Pine:
You assume that wherever you would have humanity “go” that place would be safer from the chaotic destructive natural forces. But we must spend resources on it! Another utopia in the making, if only we had an infinite amount of money ….
om–Not talking about establishing a Utopia.
Moreover, I assume that any such inevitably hard-won settlement or settlements in our Solar system—new technologies would need to be created, it would be very expensive, and there would inevitably be a lot of deaths involved in the process of creating and perfecting the necessary technology, equipment, and procedures—would, of necessity, be bare-bone, indeed, at least initially.
But, given the increasing evidence that the human race’s existence here on an Earth is far more precarious, that we have been and, likely will be in the future, subject to other often unpredictable catastrophic natural events, the smart thing to do, for the survival of the human race, is to put our “eggs” into a couple of different baskets, rather than just our current one, here on Earth.
Taking such action, it seems to me, is an urgent task.
Putting science fiction into practice is a task to be sure. Unpredictable events are kind of hard to plan for.
om–“Unpredictable” in the sense that you don’t know just when they will occur, but predictable in the sense that you know they will occur, because they have occurred several times–perhaps many times–in the past.
P.S.–I also note that, right now, we have no comprehensive surveillance system in place able to detect all the meteorites that might possibly strike the Earth.
Nor, if we were able to identify a meteorite that might strike the Earth, do we have any method available to destroy or to possibly deflect it–at this stage there are merely various proposals about how to avert such a strike.
Ted Clayton: Thanks for the additional material!
So I take it you have serious reservations about the Chicxulub scenario in general and DePalma’s research at Tanis in particular? (Love the Tanis name…)
Interesting I was aware the competing KT vulcanism theory, but I thought Alvarez et al. had pretty well nailed down Chicxulub.
Furthermore, you seem to consider today’s science has come to overvalue some Big Idea theories and present them as a rock-solid consensus, while glossing over troublesome details.
That is certainly my impression of climate change science and string theory.
Neo: A lot of insects do not eat in their adult form, after metamorphosis, which they use only for reproduction. Almost all their lives they spend in water as larvae, and fresh water bodies were not seriously damaged by asteroid impact. These larvae eat mostly the debris at the bottom of ponds and rivers, and there was enough of this organic-rich material to last for several years of reduced photosynthesis. And yes, the mammals of this period were almost all insect eaters. The most numerous insects were termites, and they need only deadwood to eat. There were a lot of this material after impact.
Snow on Pine:
But we “know” that Climate Change is going to end life on the Earth in 12 years so why are we worrying about an unpredictable but certain disaster (bad star) scenario from outer space. 🙂
After all “we” must do something starting now.
Well, its all about resources and taking from those to do what is “best” for all.
What are “we” going to do about the mega-volcanos/calderas? They aren’t hiding in space, we live with them right here on dear old Earth. And going from the big things to the little, when will the next global pandemic (1917 Flu) strike down millions? It’s all about resources and risk.
KT vulcanism is not competing explanation, it was only a small addition to much more drastic consequences of asteroid impact. The influence of mass basalt flows in Deccan province of India was regional, not global. It could not block photosynthesis worldwide, while could lead to acidification of the ocean due sulfur poisoning. Extinction of ammonites and many other marine species can be the result of these events.
This appears to be ordinary confirmation-bias in-action,
I thought they concluded that it was a seiche that affected the distant lake.
The impact event which ended mesozoic era was probably multiple, it was not only Chicxulub meteorite, but also even greater impact on the shelf near Mumbai. The basalt eruption in Deccan was probably caused by this “Shiva” impact caused by an asteroid of the 40 km diameter.
KT vulcanism is not competing explanation…
Sergey: That’s what wiki says, but other scientists do consider it a competing explanation:
_______________________________________
From UC Berkeley:
But first, let’s outline what scientists generally agree that we know about the K-T boundary….
The “intrinsic gradualists”
Those scientists falling into this category believe that the ultimate cause of the K-T extinction was intrinsic; meaning of an Earthly nature; and gradual, taking some time to occur (several million years). Two main hypotheses exist today:
(1)Volcanism: …
—https://ucmp.berkeley.edu/diapsids/extinctheory.html
________________________________________
From National Geographic:
Scientists tend to huddle around one of two hypotheses that may explain the Cretaceous extinction: an extraterrestrial impact, such as an asteroid or comet, or a massive bout of volcanism.
–https://www.nationalgeographic.com/science/prehistoric-world/dinosaur-extinction/
Only stratospheric vulcanic eruptions can have a global impact. Sulphate aerosols in lower atmosphere are quickly washed out by rains (it takes only several weeks), but in stratosphere these aerosols can reside several years. They reduce sunlight and cool the surface by 1.5 to 2 degrees, but the most important effect is reducing photosynthesis. Massive basalt outflows can release lots of sulphur, but cannot throw it into stratosphere. The dust from asteroid also can block photosynthesis for several years, completely disrupting food chains on the global scale.
Imagine if you had been on Mars when the Tharsis Bulge was (possibly) created by an impact on the other side of the planet. Talk about ringing your bell!
huxley on 4/4 @1:32pm – Yes, I have reservations about “the Chicxulub scenario in general“, especially with the emphasis on confirmation, and disinterest (if not hostility) in fuller assessments. As we saw with ‘climate’.
Tanis appears to be a “great” bone-bed (and it’s a prize name!). Possibly not quite Burgess Shale great, but a biggie. Yet it has become primarily Chicxulub. ‘We don’t need another great bone-bed, Bob, We need you to get in there and fight-fight-fight for the Yucatan Dino-Killer!’
Smithsonian noticed. The Tanis Team, hot on the Chicxulub agenda, is sparing no efforts – including such as we prefer to be kept at arms length from science – to rack up yardage and retain possession … off the science playing-field, and in a totally different League. Flags thrown, on the New Yorker play.
Fossil Site May Capture the Dinosaur-Killing Impact, but It’s Only the Beginning of the Story
Science has gotten more-delicate aspects of its anatomy pinched in tighter door-jams, on previous occasions, and the day may arrive when we chuckle affectionately at the antics of James Hansen, and the stampeding of young Robert DePalma … but Big Idea Science (Climate, String Theory, LIGO, ISS) had was a primary part of what Pres. Eisenhower was pointing at, when he explicitly include Science in his famous warning, which we usually only see edited to focus on the Military-Industrial Complex.
[Continuing with waterline work today…]
Mike K on 4/4 @2:15pm – Yes, you’re right, they do shift their focus to the seiche-explanation, and “conclude” that the site represents an example of this rare dynamic.
But first, right in the Abstract, and repeatedly throughout the paper, they acknowledge that “everything” there supports that the dynamic was actually a common-place tsunami run-up, or other common hydrologic event.
They work real hard, to ignore & move on from dominant & dominating evidence, that their site is better-explained by mechanisms other than the rare seiche.
They do this, because only a seiche can be tied to Chicxulub, and that is their pre-selected goal.
Hell Creek Formation, which hosts the Tanis site where this work is being done, is already a large & important geology & paleontology province. There is a good chance that further/additional sites in the area will shed more & better light on whether Tanis records an asteroid strike, or merely a common-place earthquake-tsunami.
Ted Clayton: I’ll take your word Chicxulub and Tanis are not as solid as I had thought from reading the news.
DePalma has no PhD and therefore would be motivated to make as much of a splash as possible. My impression is launching a career in academia these days is on par with a career as a soap opera star. Intensely competitive.
I’m also reminded of that biologist who seemed to have discovered bacteria living in Lake Mono which had replaced phosphorus with arsenic in its biochemistry. Something like that. As I recall, the discovery fizzled a few years later.
So, did they really catch the Higgs Boson?
huxley; The caveats on my down-grade of DePalma/Tanis, are dating & isotopes, which are a big part of the report. Despite whatever shenanigans, confirmation-bias, ulterior motives … if they have hi-res Dates dialed in and Isotope Signatures that are unassailable Chicxulub, then all they have to do is weather the flak. So don’t give up hope yet!
When I saw ‘glass beads’, I wondered, ‘Is that what we call microspherules now?’. But no, they’re talking little glass beebees. Otoh, these are a much more ‘real’ material to work with than microspherules (which the Younger Dryas Impact people have pretty-well defamed). But on the other hand, glass beads are a very common volcanic material.
Plus, I’m not sure about ejecta from an impact like this being able to form bulk-glass, and it being able to round-up into beads, which carry for long distances. “Tektites”, I know… These are extreme-energy ‘dispersal agents’ … there is glass on the Bikini beaches, but what fell from the sky was ‘ash’ (a gritty ‘sand’, in that case, and in the early fall from Mt St Helens). Same at Tinity. ‘Ash’ is not really what it is … but even those relatively low-energy events were beyond the strength of hot glass. Actually, so-called ash is glass-like, but not coherent; disrupted & ‘frassed’.
YD Impact people made this mistake, postulating great chunks of Icesheet ballistically launched across continents & beyond. Ice probably can’t do that.
Other people are digging up glass in various places (closer to Yucatan is popular/sensible), but then they argue with each other; and the vested authorities (Walter Alvarez & Co. & key Schools) down-play/reject all of them. ‘Not our beads’!
Are beads from the Caribbean and Mexico really from Yucatan? If they are, then I’m wrong on an important point … but that there is a lot of squabbling going on about the glass, says it’s not a point I urgently have to clear-up.
But I will now have time to properly read the paper. We buttoned up the waterline this afternoon … and the rain arrived as we finished backfilling!
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‘Alien Life’ – ET! – in a Brine Lake. And were they actual NASA employees, or just on a grant? Even if they made a nifty discovery, they WAY overplayed their winnings.
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Whether they snagged a real & true Higgs Boson or not, it’s the only game in town, and CERN owns it. But then again, I understand the raw data is available, and the bandwidth to download it is no longer a fantasy. Indeed, it’s back to a storage bottleneck, again.
I have done a test of large biomolecule modeling, which uses a similar (Government/Agency) raw data setup, and Linux code a person can find. Likewise with the Large Hadron Collider; Linux programs offered open-source.
It would be a pretty awesome trip, just to load-up a chunk of their noise and run it through the processing-code, eh?