Chicxulub Impact Crater Simulation Released; BOOM

SLAM: debunk creationism, pseudoscience, and superstitions. Discuss logic and morality.

Moderators: Alyrium Denryle, SCRawl, Thanas

User avatar
Sea Skimmer
Yankee Capitalist Air Pirate
Posts: 37039
Joined: 2002-07-03 11:49pm
Location: Passchendaele City, HAB
Contact:

Chicxulub Impact Crater Simulation Released; BOOM

Postby Sea Skimmer » 2016-11-18 04:27pm

https://www.youtube.com/watch?v=ankmTU89X_A
Direct link to simulation video. This is based on extensive actual core samples taken not long ago, and while may not be 100% accurate, its far more valid then any prior attempt to simulate the Chicxulub impact.


Article which also has video

http://www.bbc.com/news/science-environment-38019604

Asteroid strike made 'instant Himalayas'
By Jonathan Amos BBC Science Correspondent


From the section Science & Environment

Scientists say they can now describe in detail how the asteroid that wiped out the dinosaurs produced its huge crater.

The reconstruction of the event 66 million years ago was made possible by drilling into the remnant bowl and analysing its rocks.

These show how the space impactor made the hard surface of the planet slosh back and forth like a fluid.

At one stage, a mountain higher than Everest was thrown up before collapsing back into a smaller range of peaks.

"And this all happens on the scale of minutes, which is quite amazing," Prof Joanna Morgan from Imperial College London, UK, told BBC News.

The researchers report their account in this week's edition of Science Magazine.

Their study confirms a very dynamic, very energetic model for crater formation, and will go a long way to explaining the resulting cataclysmic environmental changes.

The debris thrown into the atmosphere likely saw the skies darken and the global climate cool for months, perhaps even years, driving many creatures into extinction, not just the dinosaurs.

The team spent May to June this year drilling a core through the so-called Chicxulub Crater, now buried under ocean sediments off Mexico's Yucatan Peninsula.

A 15km-wide object dug a hole in the crust 100km across and 30km deep
This bowl then collapsed, leaving a crater 200km across and a few km deep
Its central zone rebounded and relaxed, producing an inner "peak ring"
Today, much of the crater is offshore, buried under 600m of sediments
On land, it is covered by limestone deposits, but its outline is visible
It is evident in an arc of famous sinkholes referred to as cenotes

The researchers targeted a particular zone in the 200km-wide bowl known as the "peak ring", which - if earlier ideas were correct - should have contained the rocks that moved the greatest distance in the impact. These would have been dense granites lifted from almost 10km down.

And that is precisely what the team found.

"Once we got through the impact melt on top, we recovered pink granite. It was so obvious to the eye - like what you would expect to see in a kitchen countertop," recalled Prof Sean Gulick from the University of Texas at Austin, US.

But these were not normal granites, of course. They were deformed and fractured at every scale - visibly in the hand and even down at the level of the rock's individual mineral crystals. Evidence of enormous stress, of having experienced colossal pressures.
Image copyright DSmith@ECORD
Image caption The team retrieved many hundreds of metres of rock from the crater

The analysis of the core materials now fits an astonishing narrative.

This describes the roughly 15km-wide stony asteroid instantly punching a cavity in the Earth's surface some 30km deep and 80-100km across.

Unstable, and under the pull of gravity, the sides of this depression promptly started to collapse inwards.

At the same time, the centre of the bowl rebounded, briefly lifting rock higher than the Himalayas, before also falling down to cover the inward-rushing sides of the initial hole.

"If this deep-rebound model is correct (it's called the dynamic collapse model), then our peak ring rocks should be the rocks that have travelled farthest in the impact - first, outwards by kilometres, then up in the air by over 10km, and back down and outwards by another, say, 10km. So their total travel path is something like 30km, and they do that in under 10 minutes," Prof Gulick told the BBC's Science in Action programme.

Imagine a sugar cube dropped into a cup of tea. The drink's liquid first gets out of the way of the cube, moves back in and up, before finally slopping down.

When the asteroid struck the Earth, the rocks it hit also behaved like a fluid.

"These rocks must have lost their strength and cohesion, and very dramatically had their friction reduced," said Prof Morgan. "So, yes, temporarily, they behave like a fluid. It's the only way you can make a crater like this."
Media captionProf Joanna Morgan: "The model we've proven is much more catastrophic"

One of the important outcomes of the research is that it provides a useful template also to understand the surfaces of other planets.

All the terrestrial worlds and even Earth's Moon are scarred with craters just like Chicxulub.

And knowing how rocks can move vertically and horizontally in an impact will assist scientists as they attempt to interpret similar crustal features seen elsewhere in the Solar System.

The project to drill into Chicxulub Crater was conducted by the European Consortium for Ocean Research Drilling (ECORD) as part of the International Ocean Discovery Program (IODP). The expedition was also supported by the International Continental Scientific Drilling Program (ICDP).

Jonathan.Amos-INTERNET@bbc.co.uk and follow me on Twitter: @BBCAmos



So if anyone wondered if we could build a 100km diameter shaped charge out of half of a moon using 100 terratons of explosive yield to attack the Death Star 2 with, the answer is YES, because that dino killer impact caused a fully hydrodynamic rebound spike of rock to be launched 20km into the damn sky.

Not melted, not shattered, actually flowing solid rock went up like that, and then came back down still under hydrodynamic flow conditions. Which is not a really shocking discovery of science or any such thing, but its damn impressive to have it confirmed and demonstrated on such a vast basis. It also does help us understand why mountains 'work' and even clues towards what make's a continental plate, as neither 'works' when modeled as a solid.
"This cult of special forces is as sensible as to form a Royal Corps of Tree Climbers and say that no soldier who does not wear its green hat with a bunch of oak leaves stuck in it should be expected to climb a tree"
— Field Marshal William Slim 1956

User avatar
SpottedKitty
Jedi Knight
Posts: 769
Joined: 2014-08-22 08:24pm
Location: UK

Re: Chicxulub Impact Crater Simulation Released; BOOM

Postby SpottedKitty » 2016-11-18 05:16pm

The BBC article quoted has pictures of those deep granite samples. They've been shattered. The really impressive thing? The whole process inside the crater rim was pretty much over in five to ten minutes.
“Despite rumor, Death isn't cruel — merely terribly, terribly good at his job.”
Terry Pratchett, Sourcery

User avatar
Broomstick
Emperor's Hand
Posts: 24958
Joined: 2004-01-02 07:04pm
Location: Industrial armpit of the US Midwest
Contact:

Re: Chicxulub Impact Crater Simulation Released; BOOM

Postby Broomstick » 2016-11-18 05:32pm

So, if I understand this correctly, the asteroid smashed all the way through the crust and into the upper mantle?
A life is like a garden. Perfect moments can be had, but not preserved, except in memory. Leonard Nimoy.

Now I did a job. I got nothing but trouble since I did it, not to mention more than a few unkind words as regard to my character so let me make this abundantly clear. I do the job. And then I get paid.- Malcolm Reynolds, Captain of Serenity, which sums up my feelings regarding the lawsuit discussed here.

If a free society cannot help the many who are poor, it cannot save the few who are rich. - John F. Kennedy

Sam Vimes Theory of Economic Injustice

Simon_Jester
Emperor's Hand
Posts: 28806
Joined: 2009-05-23 07:29pm

Re: Chicxulub Impact Crater Simulation Released; BOOM

Postby Simon_Jester » 2016-11-18 07:47pm

Given that the asteroid was comparable in diameter to the crust's thickness, this would hardly be surprising- but it sounds like Skimmer is talking about weirder material properties and behaviors, solid rock bouncing around like the rubble of a trampoline, things like that.
This space dedicated to Vasily Arkhipov

User avatar
Sea Skimmer
Yankee Capitalist Air Pirate
Posts: 37039
Joined: 2002-07-03 11:49pm
Location: Passchendaele City, HAB
Contact:

Re: Chicxulub Impact Crater Simulation Released; BOOM

Postby Sea Skimmer » 2016-11-18 07:57pm

The maximum crater depth was right at where the top of the mantle had been, 30km depth, but the hit was so intensive the shockwave had already displaced the mantle completely from that location, with what looks to be about a 7km thickness of crust taking its place! You can see this super early in the video along the left which is the center of impact.

Then this massively rebounded, but in a manner which did not eject any mantle material from the crater. Solid material just moved under the pressure. The mountain of solid rock shot back kilometers into the sky was all crust.

It looks like the impact rock itself was disintegrated and blown out of the crater completely which is no surprise at a 20km/s impact speed. That created the iridium fallout world wide we can test for from this hit.

The fact that the crater stopped at about mantle depth isn't likely to be coincidence, it could be linked to the relative size of the impactor vs the crust. I could also be linked to the fact that the mantle is probably hydrodynamic at all times at very slow speeds, which would give it greater resistance to shock then the crust. Just like composite armor ect.. logical that this scales up. Its probably a matter of both and more.

Anti tank shaped charges work hydrodynamically too. It might be confusing because HEAT style charges are very fast, while some of the total travel speeds here are very slow, 50m/s slow even, though they say the time range estimates are pretty uncertain, 1-10 minute sort of range. The answer to that is that what matters is pressure and not speed. The impactor was physically huge and about equally hard to the crust, stuff HAD to get out of the way, and since it's already solid....this moves us into hydrodynamics.
"This cult of special forces is as sensible as to form a Royal Corps of Tree Climbers and say that no soldier who does not wear its green hat with a bunch of oak leaves stuck in it should be expected to climb a tree"
— Field Marshal William Slim 1956

Simon_Jester
Emperor's Hand
Posts: 28806
Joined: 2009-05-23 07:29pm

Re: Chicxulub Impact Crater Simulation Released; BOOM

Postby Simon_Jester » 2016-11-18 09:49pm

Hydrodynamics, here, is the science of the movement of non-compressible substances. Thus named because water is not compressible, and water flows all the time.

Rocks do not normally flow, at least until they are heated to the melting point. But with sufficient pressure, they will flow even in the absence of sufficient heat.

[Did I get that right?]
This space dedicated to Vasily Arkhipov

User avatar
Iroscato
Jedi Council Member
Posts: 2238
Joined: 2011-02-07 03:04pm
Location: Great Britain (It's great, honestly!)

Re: Chicxulub Impact Crater Simulation Released; BOOM

Postby Iroscato » 2016-11-18 10:38pm

So, this thing hit the planet at mach 60 according to my friend the calculator. That would've been a hell of a (last) thing to see.
Yeah, I've always taken the subtext of the Birther movement to be, "The rules don't count here! This is different! HE'S BLACK! BLACK, I SAY! ARE YOU ALL BLIND!?

- Raw Shark

Destiny and fate are for those too weak to forge their own futures. Where we are 'supposed' to be is irrelevent.

- SirNitram (RIP)

User avatar
Sea Skimmer
Yankee Capitalist Air Pirate
Posts: 37039
Joined: 2002-07-03 11:49pm
Location: Passchendaele City, HAB
Contact:

Re: Chicxulub Impact Crater Simulation Released; BOOM

Postby Sea Skimmer » 2016-11-19 12:44am

Simon_Jester wrote:Hydrodynamics, here, is the science of the movement of non-compressible substances. Thus named because water is not compressible, and water flows all the time.


In broad strokes Hydrodynamics is the study of fluid in motion. This does not depend on if a material is compressible or not, water is compressible to a noteworthy degree under confined pressure. Just not really at say, the pressure of tap water. Hydrodynamic penetration is a subset of this field. Fluids all want to behave in a similar manner, no matter what they are actually made of. Property of the universe kind of thing.

Solids do compress a little bit, but when you're talking rock and '15km wide hold' the compression can account for very little material displacement. The enormous rebound effect of an impact like this is linked to the release of that compressed energy though.

But big thing is previously we would have assumed that the rebound ejected ground broke up into chunks or dust ect blown far away.......not that so much of it it flowed as one immense solid that splashed back down in place so perfectly, with only a portion was blown loose as debris.


Rocks do not normally flow, at least until they are heated to the melting point.


When you heat a solid rock to melting point, you actually eliminate the grain structure of the rock and all the molecules become free moving as a liquid. That is what melting means. Cool that rock back down and you will get a different rock, in fact you would get a different type of rock with an entirely new grain structure, and depending on the details, all kinds of new molecules can form too. The rock can outright form new rock by reacting with the AIR at that point. Metalworking is highly dependent on that kind of thing.




But with sufficient pressure, they will flow even in the absence of sufficient heat.


With sufficient pressure the rock structure, with its grain more or less intact, will flow like a fluid, is what this all demonstrate. The whole structure of the rock has moved, and then gotten completely normal again. This means stuff can happen like bending a rock formation into a curve....not in millions of years but seconds or minutes.

If you want a simple way to think about it, for reasons of physics the internal 'friction' that makes a solid a solid is simply being temporarily negated, but not the bonds between molecules. Once enough energy is absorbed or the stress wave finishes passing the friction is back and everything is normal again.

This is why a HEAT charge made of aluminum can go through armor made of steel which is superior in every mechanical property. Some of those properties like hardness have been negated for a moment until enough energy is absorbed in the motion, and why the hell that works remains unexplained.

Just for comparison, the actual surface temperatures of the metal jets involved are perhaps 500C for small sized RPG style warheads, though areas of high stress as the jet forms can be locally much hotter. This is not a 100% efficient process, like anything else in real life, and that's why hydrodynamic penetration for weapons, or giant rocks, or weapons made from giant rocks, does not equal infinite penetration. As opposed to the fact that if you pour one cup of water into another cup of water, the water all mixes/penetrates infinitely at the molecular level...because it's all a liquid by default.
"This cult of special forces is as sensible as to form a Royal Corps of Tree Climbers and say that no soldier who does not wear its green hat with a bunch of oak leaves stuck in it should be expected to climb a tree"
— Field Marshal William Slim 1956

User avatar
Broomstick
Emperor's Hand
Posts: 24958
Joined: 2004-01-02 07:04pm
Location: Industrial armpit of the US Midwest
Contact:

Re: Chicxulub Impact Crater Simulation Released; BOOM

Postby Broomstick » 2016-11-19 02:45am

Doesn't all that moving around heat the rock? Wouldn't at least some of the energy be dissipated as heat?
A life is like a garden. Perfect moments can be had, but not preserved, except in memory. Leonard Nimoy.

Now I did a job. I got nothing but trouble since I did it, not to mention more than a few unkind words as regard to my character so let me make this abundantly clear. I do the job. And then I get paid.- Malcolm Reynolds, Captain of Serenity, which sums up my feelings regarding the lawsuit discussed here.

If a free society cannot help the many who are poor, it cannot save the few who are rich. - John F. Kennedy

Sam Vimes Theory of Economic Injustice

Simon_Jester
Emperor's Hand
Posts: 28806
Joined: 2009-05-23 07:29pm

Re: Chicxulub Impact Crater Simulation Released; BOOM

Postby Simon_Jester » 2016-11-19 03:53am

Chimaera wrote:So, this thing hit the planet at mach 60 according to my friend the calculator. That would've been a hell of a (last) thing to see.
From geosynchronous orbit through a telescope, maybe.

Closer in? No thanks!
This space dedicated to Vasily Arkhipov

User avatar
Sea Skimmer
Yankee Capitalist Air Pirate
Posts: 37039
Joined: 2002-07-03 11:49pm
Location: Passchendaele City, HAB
Contact:

Re: Chicxulub Impact Crater Simulation Released; BOOM

Postby Sea Skimmer » 2016-11-19 03:58pm

Broomstick wrote:Doesn't all that moving around heat the rock? Wouldn't at least some of the energy be dissipated as heat?


Yes. Just not enough to induce any permanent change in the rock typically. t the boundary layer where crust rock is actually in or near direct contact with asteroid rock absurd amounts of heating will take place, to the point of vaporizing some rock. But we already had lots of evidence for that kind of direct skin/skin kind of contact event.

Conversion of KE into heat though requires that a material be physically able to resist the passage of the KE, and absorb it as heat while doing so. What happened here was the KE induced enormous fluid displacement of material before any of that had time to happen.

Eventually all energy was consumed either work accomplished displacing solid material, or conversion into heat. Once the KE energy dropped too low for the crust to remain hydrodynamic it simpler reverted to solid again, wherever it happened to be. One result of that was that the walls of the crater collapsed back into the hole within a few minutes of impact.
"This cult of special forces is as sensible as to form a Royal Corps of Tree Climbers and say that no soldier who does not wear its green hat with a bunch of oak leaves stuck in it should be expected to climb a tree"
— Field Marshal William Slim 1956


Return to “Science, Logic, And Morality”

Who is online

Users browsing this forum: No registered users and 7 guests