Hudders

Dinosaurs wiped out by asteroid or comet? New study suggests a faster smaller comet rather than a bigger slower asteroid.

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Dinosaur-killing space rock 'was a comet'

The space rock that hit Earth 65m years ago and is widely implicated in the end of the dinosaurs was probably a speeding comet, US scientists say.

Researchers in New Hampshire suggest the 180km-wide Chicxulub crater in Mexico was carved out by a smaller object than previously thought.

Many scientists consider a large and relatively slow moving asteroid to have been the likely culprit.

Details were outlined at the 44th Lunar and Planetary Science Conference.

But other researchers were more cautious about the results.

"The overall aim of our project is to better characterise the impactor that produced the crater in the Yucatan peninsula [in Mexico]," Jason Moore, from Dartmouth College in New Hampshire, told BBC News.

The space rock gave rise to a global layer of sediments enriched in the chemical element iridium, in concentrations much higher than naturally occurs; it must have come from outer space.

Extra-terrestrial chemistry

However, in the first part of their work, the team suggests that frequently quoted iridium values are incorrect. Using a comparison with another extraterrestrial element deposited in the impact - osmium - they were able to deduce that the collision deposited less debris than has previously been supposed.

The recalculated iridium value suggests a smaller body hit the Earth. So for the second part of their work, the researchers took the new figure and attempted to reconcile it with the known physical properties of the Chicxulub impact.

For this smaller space rock to have produced a 180km-wide crater, it must have been travelling relatively quickly. The team found that a long-period comet fitted the bill much better than other possible candidates.

"You'd need an asteroid of about 5km diameter to contribute that much iridium and osmium. But an asteroid that size would not make a 200km-diameter crater," said Dr Moore.

"So we said: how do we get something that has enough energy to generate that size of crater, but has much less rocky material? That brings us to comets."

Dr Moore's colleague Prof Mukul Sharma, also from Dartmouth College, told BBC News: "You would need some special pleading for an asteroid moving very rapidly - although it is possible. But of the comets and asteroids we have looked at in the skies, the comets are the ones that are moving very rapidly."

Long-period comets are balls of dust, rock and ice that are on highly eccentric trajectories around the Sun. They may take hundreds, thousands or in some cases even millions of years to complete one orbit.

The extinction event 65 million years ago is now widely associated with the space impact at Chicxulub. It killed off about 70% of all species on Earth in just a short period of time, most notably the non-avian dinosaurs.

The enormous collision would have triggered fires, earthquakes and huge tsunamis. The dust and gas thrown up into the atmosphere would have depressed global temperatures for several years.

Lost in space

Dr Gareth Collins, who researches impact cratering at Imperial College London, described the research by the Dartmouth team as "nice work" and "thought-provoking".

But he told BBC News: "I don't think it is possible to accurately determine the impactor size from geochemistry.

"Geochemistry tells you - quite accurately - only the mass of meteoritic material that is distributed globally, not the total mass of the impactor. To estimate the latter, one needs to know what fraction of the impactor was distributed globally, as opposed to being ejected to space or landing close to the crater."

He added: "The authors suggest that 75% of the impactor mass is distributed globally, and hence arrive at quite a small-sized impactor, but in reality this fraction could be lower than 20%."

That could keep the door open for a bigger, more slowly moving asteroid.

The authors accept this point, but cite recent studies suggesting mass loss for the Chicxulub impact was between 11% and 25%.

In recent years, several space objects have taken astronomers by surprise, serving as a reminder that our cosmic neighbourhood remains a busy place.

On 15 February this year, 2012 DA14 - an asteroid as large as an Olympic swimming pool - raced past the Earth at a distance of just 27,700km (17,200mi). It had only been discovered the previous year.

And on the same day, a 17m space rock exploded over Russia's Ural mountains with an energy of about 440 kilotonnes of TNT. About 1,000 people were injured as the shockwave blew out windows and rocked buildings.

Some 95% of the near-Earth objects larger than 1km have been discovered. However, only about 10% of the 13,000 - 20,000 asteroids above the size of 140m are being tracked.

There are probably many more comets than near-Earth asteroids, but Nasa points out they spend almost all of their lifetimes at great distances from the Sun and Earth, so that they contribute only about 10% to the census of larger objects that have struck the Earth.

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On ‎23‎/‎03‎/‎2013 at 4:38 PM, Hudders said:
Quote

Dinosaur-killing space rock 'was a comet'

 

The space rock that hit Earth 65m years ago and is widely implicated in the end of the dinosaurs was probably a speeding comet, US scientists say.

 

Researchers in New Hampshire suggest the 180km-wide Chicxulub crater in Mexico was carved out by a smaller object than previously thought.

Many scientists consider a large and relatively slow moving asteroid to have been the likely culprit.

Details were outlined at the 44th Lunar and Planetary Science Conference.

But other researchers were more cautious about the results.

"The overall aim of our project is to better characterise the impactor that produced the crater in the Yucatan peninsula [in Mexico]," Jason Moore, from Dartmouth College in New Hampshire, told BBC News.

The space rock gave rise to a global layer of sediments enriched in the chemical element iridium, in concentrations much higher than naturally occurs; it must have come from outer space.

 

Extra-terrestrial chemistry

 

However, in the first part of their work, the team suggests that frequently quoted iridium values are incorrect. Using a comparison with another extraterrestrial element deposited in the impact - osmium - they were able to deduce that the collision deposited less debris than has previously been supposed.

The recalculated iridium value suggests a smaller body hit the Earth. So for the second part of their work, the researchers took the new figure and attempted to reconcile it with the known physical properties of the Chicxulub impact.

For this smaller space rock to have produced a 180km-wide crater, it must have been travelling relatively quickly. The team found that a long-period comet fitted the bill much better than other possible candidates.

"You'd need an asteroid of about 5km diameter to contribute that much iridium and osmium. But an asteroid that size would not make a 200km-diameter crater," said Dr Moore.

"So we said: how do we get something that has enough energy to generate that size of crater, but has much less rocky material? That brings us to comets."

Dr Moore's colleague Prof Mukul Sharma, also from Dartmouth College, told BBC News: "You would need some special pleading for an asteroid moving very rapidly - although it is possible. But of the comets and asteroids we have looked at in the skies, the comets are the ones that are moving very rapidly."

Long-period comets are balls of dust, rock and ice that are on highly eccentric trajectories around the Sun. They may take hundreds, thousands or in some cases even millions of years to complete one orbit.

The extinction event 65 million years ago is now widely associated with the space impact at Chicxulub. It killed off about 70% of all species on Earth in just a short period of time, most notably the non-avian dinosaurs.

The enormous collision would have triggered fires, earthquakes and huge tsunamis. The dust and gas thrown up into the atmosphere would have depressed global temperatures for several years.

 

Lost in space

 

Dr Gareth Collins, who researches impact cratering at Imperial College London, described the research by the Dartmouth team as "nice work" and "thought-provoking".

But he told BBC News: "I don't think it is possible to accurately determine the impactor size from geochemistry.

"Geochemistry tells you - quite accurately - only the mass of meteoritic material that is distributed globally, not the total mass of the impactor. To estimate the latter, one needs to know what fraction of the impactor was distributed globally, as opposed to being ejected to space or landing close to the crater."

He added: "The authors suggest that 75% of the impactor mass is distributed globally, and hence arrive at quite a small-sized impactor, but in reality this fraction could be lower than 20%."

That could keep the door open for a bigger, more slowly moving asteroid.

The authors accept this point, but cite recent studies suggesting mass loss for the Chicxulub impact was between 11% and 25%.

In recent years, several space objects have taken astronomers by surprise, serving as a reminder that our cosmic neighbourhood remains a busy place.

On 15 February this year, 2012 DA14 - an asteroid as large as an Olympic swimming pool - raced past the Earth at a distance of just 27,700km (17,200mi). It had only been discovered the previous year.

And on the same day, a 17m space rock exploded over Russia's Ural mountains with an energy of about 440 kilotonnes of TNT. About 1,000 people were injured as the shockwave blew out windows and rocked buildings.

Some 95% of the near-Earth objects larger than 1km have been discovered. However, only about 10% of the 13,000 - 20,000 asteroids above the size of 140m are being tracked.

There are probably many more comets than near-Earth asteroids, but Nasa points out they spend almost all of their lifetimes at great distances from the Sun and Earth, so that they contribute only about 10% to the census of larger objects that have struck the Earth.

 

Source.

 

Wiped out during the flood, which possibly involved an asteroid shower

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On 14/11/2016 at 7:49 PM, Hudders said:

Wut?

My theory on the disappearance of the dinosaurs

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And what evidence do you have for this?

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If the dinosaurs were wiped out by or during the flood, then the flood must have been 66 million years ago, many tens of millions of years before humans existed. This is because there is strong evidence that all dinosaurs except birds became extinct 66 million years ago.

A glib, "the flood did it" is just not good enough.

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On 29/11/2016 at 5:46 AM, Hudders said:

And what evidence do you have for this?

Something cause the complete extinction of the dinosaurs at the K/T boundary

The flood has to occur sometime, no modern creationist claims it created the entire sedimentary layers, so we need to place it somewhere and thats there some creationists including me place it.

On 29/11/2016 at 0:18 PM, Russell said:

If the dinosaurs were wiped out by or during the flood, then the flood must have been 66 million years ago, many tens of millions of years before humans existed. This is because there is strong evidence that all dinosaurs except birds became extinct 66 million years ago.

A glib, "the flood did it" is just not good enough.

I don't accept radiometric dating figures except for maybe Carbon 14.

And so I believe man and dinosaurs lived together

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What do you think of Behemoth and Leviathan in Job? @Russell

 

Doesn't sound like a crocodile or hippo to me

Edited by SDA

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19 minutes ago, SDA said:

What do you think of Behemoth and Leviathan in Job? @Russell

 

Doesn't sound like a crocodile or hippo to me

I think they're awesome.

1 hour ago, SDA said:

I don't accept radiometric dating figures except for maybe Carbon 14.

Why not?

1 hour ago, SDA said:

And so I believe man and dinosaurs lived together

Where's the evidence for this?

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33 minutes ago, Fortigurn said:

I think they're awesome.

Awesome dinosaurs?

33 minutes ago, Fortigurn said:

Why not?

It cannot be verified, might be well educated predictions but only human memory can prove what occured in history.

And https://en.m.wikipedia.org/wiki/Mary_Higby_Schweitzer#Discoveries

36 minutes ago, Fortigurn said:

Where's the evidence for this?

http://www.untoldsecretsofplanetearth.com/store/dire-dragons/

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Quote

 

I don't accept radiometric dating figures except for maybe Carbon 14.

And so I believe man and dinosaurs lived together

 

lol...... 

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7 hours ago, SDA said:

The topic of soft dinosaur tissue has been doing the rounds again, and so it could be useful to explain some of the details about this topic. Very briefly, this is what the issue is about:
Mary Schweitzer is a palaeontologist who discovered remnants of soft tissue in fossilised dinosaur remains. The science community has viewed her research as extraordinary, because it has opened the door to new discoveries about preservation and decay.  Meanwhile, certain religious organisations have used her research to assert that dating methods are wrong, because soft tissue couldn’t possibly last as long as she says.
So, the question is this: Does her research show that dating methods are wrong, because there couldn’t possibly be soft tissue after 60million years; or, does her research show that there are situations in which tissue remnants can be persevered for extraordinarily long periods of time? 

Let’s look into this further…

Mary Schweitzer’s journey into this research started in 1992 after she had recently graduated and was working in a laboratory. She was preparing microscope slides of a 60-million year old Tyrannosaurus rex specimen, and discovered what appeared to be blood cells. Her mentor (renowned palaeontologist Jack Horner) asked her what she thought she was seeing, and she replied, “Well, I know they can't be blood cells, but they're in the right place, the right location, the right size, and they're nucleated." He challenged her to prove they were not red blood cells. So she set out to prove they weren’t - and that effort led to her PhD. [1] By doing various tests she found that somewhere in the fossil bones were compounds that were consistent with heme, which is a small, relatively stable iron-containing molecule that gives blood its red colour, and is the key oxygen-carrying component of the hemoglobin protein. (This bit about ‘iron-containing molecules’ is important - we’ll come back to that later.)  She published her research in 1997, explaining her conclusions that the T.rex fossil contained fragments of hemoglobin molecules (not actual blood cells).

Schweitzer continued to do more of this research, and soft tissue topic surfaced again in 2005, when Schweitzer and her co-authors reported the discovery of intact blood vessels and other soft tissues in bone from a 65-million-year-old specimen of T.rex[2]. As before, scientists were initially skeptical of these findings, as no-one ever imagined soft tissue could survive this long; and although some researchers attempted alternative explanations[3], these were never successfully substantiated, and Schweitzer’s research stood.

Schweitzer kept on investigating how it could be possible for rock-hard fossils that are tens of millions of years old, to have remnants of soft tissues inside them. It must be noted that at no stage has her research ever provided anything that would cast doubt on established dating methods. For example, the samples used for her 2005 paper are from one of the better dated dinosaur bones known to exist. The age of this bone is based on 86 separate chemical analyses on three different kinds of minerals, based on four independent radiometric decay series.[4] The dinosaur they were studying came from the Hell’s Creek Formation, which is one of the more famous and intensely studied dinosaur fossil sites spreading across areas of Montana, South Dakota, and North Dakota. This area and its fossils have been rigorously and independently dated on numerous occasions, always producing the same consistent results.

It wasn’t dating methods that her research refuted, but rather existing models of degradation, decay and fossilisation. Schweitzer and her team hypothesised that these tissues were “remnants of original proteinaceous material, highly altered by beta oxidation of original proteins to form long-chain hydrocarbon polymers”. If this was the case, then mechanisms must exist to allow their persistence across geological time. THAT had been the focus of Schweitzer’s research.[5]

In 2014, she published further research showing how soft tissue structures can be preserved over millions of years, through the way which iron and oxygen chemistry “contributes to preservation in deep time, perhaps by both free-radical-mediated fixation and anti-microbial activity”.[6] Because Schweitzer’s team always observed iron particles in association with these soft tissues, this is what they investigated further. Their research explained both the association of iron with many exceptionally preserved fossils, and the enhanced preservation of tissues, cells and molecules over deep time. As a result of this research, iron and oxygen chemistry are now seen to play key roles in the preservation of biomaterials after death, because it showed that iron released from some proteins becomes available for free-radical chemistry with oxygen, leading to protein and lipid cross-linking, tissue fixation, and resistance to enzymatic/bacterial degradation.   There are three possibilities for this: The iron may be directly protecting proteins by blocking certain degradation activities; or, it may be providing protection indirectly by binding to oxygen, and thus preventing oxidative damage; or, it is outcompeting bacterial mechanisms that would lead to decay.[7]  Interestingly enough, during this research another team found similar results doing a different study, which also showed that iron influences preservation of biomolecules across geological time, further supporting the longevity of some iron-containing biomolecules[8]. 

Over the years, Schweitzer’s research certainly got the attention of science community, and it placed her under intense scrutiny. In her words: “There was so much interest. There was so much criticism. But I had data…   I learned so much through the process. I'm so grateful. I learned how to be a careful scientist.”[9]

But if Schweitzer’s research intrigued the science community - it sent the creationist world into a frenzy, as young earth creationists sought to use her research to discredit established dating methods. Their claim is that it is simply not possible for soft-tissue to last tens of millions of years; ergo, dating methods are flawed and in doubt. 

Schweitzer has repeatedly tried to refute these claims, and to explain the reasons why this is not what her research reveals. For example, in one interview she said, "One thing that does bother me, though, is that young earth creationists take my research and use it for their own message, and I think they are misleading people about it. Pastors and evangelists, who are in a position of leadership, are doubly responsible for checking facts and getting things right, but they have misquoted me and misrepresented the data”[10]
In another article for the Smithsonian she noted that “[Christians] treat you really bad. They twist your words and they manipulate your data.”[11]

What makes her patience towards young earth creationists more notable, is that she was once one herself. Again, in her own words: “One day, shortly after I finished that program, I saw that palaeontologist Jack Horner — everyone knew him in Montana — was teaching a class on campus at Montana State. I went to class that first day of the semester and after his introductory lecture, I walked up and said, "Hi, Jack. I am a young earth creationist, and I'm going to convince you you're wrong about evolution. Can I sit in on your class?"
He said, "I'm Jack. I'm an atheist. Have a seat."
And instead of calling me out or making fun of my beliefs, he showed me data. No one had ever shown me data before. Often in the Christian community people aren’t talking about scientific data. Instead, Christians may hear about scientists: "They're evil. They don't believe in God. They're atheists.” But many Christians haven’t heard how much data supports an ancient earth and evolution. Nobody’s told them.
Jack never tried to change my mind about anything. He just said, "Here's the data." And about halfway through that first semester, I began to see that my young earth views could not be supported in light of all the data. I knew God and was not willing to turn away from him. And I began to see that the two weren’t mutually exclusive as I had been taught.”[12]

The point has to be made then, that Schweitzer, having been a young earth creationist herself, fully understands both sides of the debate. If the scientist responsible for the research refutes the claims of young earth creationists - then it is her opinion we should be favouring. It's her research after all! 

Schweitzer’s research has been truly ground breaking. She upended what we knew about preservation, and then through careful research has begun to find answers to the problem. Lately, those answers have been corroborated by independent research teams who are finding similar results. So what her research has shown, is not that dating methods are shaky, but there are preservation mechanisms at work that we previously did not know about or understand.  Through all this, she has remained a dedicated Christian who has been an inspirational role-model for those who have sought to find a balance between their faith in God and their love for the sciences.


[1] Marcia Bosscher, The Unlikely Paleontologist: An Interview with Mary Schweitzer (Part 1) (12 Jul 2016) https://goo.gl/U8Pm6v
[2] MH Schweitzer et al, Soft-Tissue Vessels and Cellular Preservation in Tyrannosaurus rex (Science, 2015) 307(5717):1952-1955
[3] TG Kaye, G Gaugler, Z Sawlowicz, Dinosaurian Soft Tissues Interpreted as Bacterial Biofilms (PLoS ONE , 2008) 3 (7): e2808. doi:10.1371/journal.pone.0002808
[4] Gary Hurd, Dino Blood Redux, (TalkOrigins, 2005) https://goo.gl/XjIDjz
[5] MH Schweitzer, J Wittmeyer, J Horner, Soft tissue and cellular preservation in vertebrate skeletal elements from the Cretaceous to the present (Proceedings of the Royal Society, 22 Jan 2007) DOI: 10.1098/rspb.2006.3705
[6] MH Schweitzer et al, A role for iron and oxygen chemistry in preserving soft tissues, cells and molecules from deep time (Proc. R. Soc. B., 2014) 281: 20132741. http://dx.doi.org/10.1098/rspb.2013.2741
[7] MH Schweitzer et al,  A role for iron and oxygen chemistry in preserving soft tissues, cells and molecules from deep time (Proc. R. Soc. B, 2014) 281: 20132741. http://dx.doi.org/10.1098/rspb.2013.2741
[8] DE Greenwalt et al, Hemoglobin-derived porphyrins preserved in a Middle Eocene blood- engorged mosquito (Proceedings of the National Academy of Sciences USA, 2014) 5. (doi:10.1073/pnas.1310885110)
[9] Marcia Bosscher, The Unlikely Paleontologist: An Interview with Mary Schweitzer (Part 2) (13 Jul 2016) https://goo.gl/2F2wjm
[10] Emily Ruppel, Not So Dry Bones: An interview with Mary Schweitzer (BioLogos Blog, 21 Jul 2014) https://goo.gl/SgBpqD
[11] Helen Fields, Dinosaur Shocker (Smithsonian.com, May 2006) https://goo.gl/JglVjj
[12] Marcia Bosscher, The Unlikely Paleontologist: An Interview with Mary Schweitzer (Part 1) (12 Jul 2016) https://goo.gl/U8Pm6v

 

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3 hours ago, Flappie said:

I thought you said they were wiped out by the flood?

Yeah, "There were a class of very large animals which perished at the flood. God knew that the strength of man would decrease, and these mammoth animals could not be controlled by feeble man."

Maybe an exceptional few were taking onto the ark, I'm not sure how close Job was to the flood.

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That book you put up as evidence for humans and dinosaurs living together mostly has stuff from the middle ages, a long time after the flood. So did more than an exceptional few survive, or is that book dodgy?

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1 hour ago, MikeP said:

The age of this bone is based on 86 separate chemical analyses on three different kinds of minerals, based on four independent radiometric decay series.

I thought scientists cannot date fossils directly and just infer date ranges from the above and below rocks?

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7 minutes ago, Flappie said:

That book you put up as evidence for humans and dinosaurs living together mostly has stuff from the middle ages, a long time after the flood. So did more than an exceptional few survive, or is that book dodgy?

Not sure, they could be unknown creatures that aren't dinosaurs. Some of the stuff is abit iffy (looks almost like cave drawings, so identification is debateable) in the book, other parts seem okay.

 

 

Edited by SDA

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I think you need to look a bit closer, and you'll realise that all of them are either unknown creates that aren't dinosaurs, a bit iffy, or simply figments of someone's imagination. I saw a vase once with Heracles fighting the Hydra, am I to believe that was a real creature?

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16 minutes ago, Flappie said:

I saw a vase once with Heracles fighting the Hydra, am I to believe that was a real creature?

Probably not, but it raises the question do some things come purely from the imagination or are they based very loosely on something real?

Abit off topic but it has relevance for:

- The Ontological argument

- For understand what exactly is creativity.

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9 hours ago, SDA said:

It cannot be verified, might be well educated predictions but only human memory can prove what occured in history.

That is categorically untrue. That's why forensics is a science, and why geological research can find oil and minerals. If you can't support your claims about science with actual evidence, please don't make them. We have rules on this forum for that situation.

9 hours ago, SDA said:

There is no evidence there that dinosaurs existed with humans. Vance Nelson's work is gibberish, and has absolutely no support within the scientific community. He just makes things up. He is a rabid Young Earth Creationist, and has no relevant scientific qualifications whatsoever, so he doesn't even know what he is talking about.

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20 minutes ago, SDA said:

Probably not, but it raises the question do some things come purely from the imagination or are they based very loosely on something real?

Abit off topic but it has relevance for:

- The Ontological argument

- For understand what exactly is creativity.

Even if the imagination is based on something, it could be loosely based on a depiction or description provided by someone else. Any likeness to a dinosaur is much more likely to be coincidental. That dude uses an Egyptian depiction of what he claims are dinosaurs (because of the long necks), but when you look at the feet/head/tail, you quickly realise it's just a cat with a really long neck (and not a real animal).

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2 minutes ago, Flappie said:

Even if the imagination is based on something, it could be loosely based on a depiction or description provided by someone else. Any likeness to a dinosaur is much more likely to be coincidental. That dude uses an Egyptian depiction of what he claims are dinosaurs (because of the long necks), but when you look at the feet/head/tail, you quickly realise it's just a cat with a really long neck (and not a real animal).

Where can I view the images online for free in high quality? So I can hear your explanations for ones that I can't work out

Edited by SDA

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Of all the images in the entire book? No idea; you'll have to find them individually.

Here's the one I was talking about: Link

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7 minutes ago, Flappie said:

Of all the images in the entire book? No idea; you'll have to find them individually.

Here's the one I was talking about: Link

SDA, what evidence is there that these are dinosaurs? What did the Egyptians call them? If dinosaurs existed at the same time as humans, where are all the fossil remains and all the depictions in artwork and all the descriptions in texts? This is just ludicrous.

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For the record, I don't know if that one has made it in the book, since I don't have it. He mentioned it in a video I saw that I now can't find. It's just an easy example of something loosely based on something real, but clearly not, being interpreted as a dinosaur.

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