impact thoughts and theory

[catfish]

hello people i watched a documentary about ancient egyptian glass .

http://www.youtube.com/watch?v=-12sKXZ7W8c

and it got me thinking about other impacts in history ,that may of been seen by our ancestors .

hearing about the hot gas plume the impact creates got me thinking about iron age hill forts in our

group of islands that had burnt rocks, some of them melted and dripped onto the rocks below .

could a comet or something else from outerspace do this or was it a fancy and quite resource wasting way of cementing rocks together ?

http://www.youtube.com/watch?v=U6b0aawLA7o

the quality of this video isnt great but you get an idea .

Edited September 14, 2013 by catfish

[catfish]

did anyone have any ideas on the vitrified rocks mostly found on the top ?

i think the amount of effort to do it firstly would of out weighed any benefit

to generate the enough heat to melt rocks and then drip onto rocks below is hot .

how many trees to generate enough heat times that by how many hillforts = shit loads .

maybe just maybe an astrological event ?

[johnnyneuro]

Inuit communities (in Greenland?) had iron tools made from meteorites long before iron smelting was discovered.

[Ishmael]

iron age man did know how to melt rocks, and not only to smelt iron out of them. http://skeptoid.com/episodes/4326

[catfish]

iron age man did know how to melt rocks, and not only to smelt iron out of them. http://skeptoid.com/episodes/4326

nice read . it doent explain why they melted the rocks yes its been proven they could melt rocks but why is my question .

im not thinking nuclear explosion more comet debits .

[Ishmael]

nice read . it doent explain why they melted the rocks yes its been proven they could melt rocks but why is my question .

im not thinking nuclear explosion more comet debits .

I think they did it to make their walls more difficult to break down under cover of darkness etc, they were warlike fuckers in the iron age and the iron masters who could melt rocks and make iron implements and weapons were like gods to them.

[catfish]

do you know how much effort is involved in making rocks vitrify ? how many trees ?

also why were some only done on half of the fort ?

there needs to be a map with them all marked that have it the ones that dont to see for a patterns

were there some in england , wales or ireland ?

are you aware of a comet c560 a.d approx .

[distracted]

impacts from space don't melt rocks, they don't melt anything, it is all about energy transfer, it is maybe hard to explain, not sure, ask if I am not getting my point across...... when a projectile hits the surface @ upwards of 17 km per second, (we will ignore the effect of the compressed atmosphere ahead of the projectile as it might just muddy things) the impact of the projectile on the rock compresses the crystalline structure of the rocks and minerals in the surface (and the atomic structure of the mineral) the minerals are compressed into the minimum compression, as close as the atoms can get, far beyond the creation of diamond, then the compression passes and everything rebounds: the pressure has gone and as a consequence the compression reverses, and reverses without resistance close to the surface, so that the decompression flows backwards towards the impact point, this is why a crater is formed. It is the collapse of the structure of the rock through decompression, not actual melting, the effect is the same in essence, as glass is formed but isn't heat induced and the difference can be seen on very close inspection in some cases as the collapse of the rocks crystalline structure isn't always perfect and doesn't cover all mineral phases equally. most importantly when tghinking about hill forts though is that decompression capable of destroying a rocks structure also results in a crater as the atmosphere cannot contain the decompression so material sprays out from the compression point

vitrified high points might point to pyres more than strikes by meteorites which is vanishingly improbable

Edited October 17, 2013 by distracted

[Ishmael]

@@catfish, check out the link in my previous post, there's a lot of research on this going back many years.

[catfish]

impacts from space don't melt rocks, they don't melt anything, it is all about energy transfer, it is maybe hard to explain, not sure, ask if I am not getting my point across...... when a projectile hits the surface @ upwards of 17 km per second, (we will ignore the effect of the compressed atmosphere ahead of the projectile as it might just muddy things) the impact of the projectile on the rock compresses the crystalline structure of the rocks and minerals in the surface (and the atomic structure of the mineral) the minerals are compressed into the minimum compression, as close as the atoms can get, far beyond the creation of diamond, then the compression passes and everything rebounds: the pressure has gone and as a consequence the compression reverses, and reverses without resistance close to the surface, so that the decompression flows backwards towards the impact point, this is why a crater is formed. It is the collapse of the structure of the rock through decompression, not actual melting, the effect is the same in essence, as glass is formed but isn't heat induced and the difference can be seen on very close inspection in some cases as the collapse of the rocks crystalline structure isn't always perfect and doesn't cover all mineral phases equally. most importantly when tghinking about hill forts though is that decompression capable of destroying a rocks structure also results in a crater as the atmosphere cannot contain the decompression so material sprays out from the compression point

vitrified high points might point to pyres more than strikes by meteorites which is vanishingly improbable

done my head in after the 3rd sentence ill try later when im awake more .

how about comet bits not acomet that went on to hit bolivia .

stories of a dragon in the sky that slit up into 7 pieces .

if objects from space dont melt rock why do we have glass in the desert ect .

just asking like

some forts are vitrified in places some inside some external one has it on one side and not the other .

there is no pattern if it was done for a purpose what was it ?

unless it was done by another force i dont know

Edited October 17, 2013 by catfish

[Ishmael]

here's the article I linked to. It's not high science just a blogger's review of the situation but it covers a lot of ground and I found it interesting.

The Mystery of the Vitrified Forts

About sixty prehistoric stone forts in Scotland have vitrified walls, where the stone was melted into glass. How was it done?

For over 250 years, archaeologists studying ancient Scottish ruins have reported a type of construction said to defy explanation. About sixty of these rough stone wall enclosures have been found throughout Scotland, and even a few scattered across mainland Europe. Most are prehistoric. Called vitrified forts, they're notable for a unique and surprising feature. The rocks that make up the walls were originally stacked dry, with no mortar; but have been fused together into a solid surface through a process called vitrification, the transformation into glass. How can rock be melted into glass using prehistoric technology? Some say that it can't because the temperatures required to do it are far too high, and that the only plausible explanation is an ancient atomic blast.

Stories of primitives possessing advanced technologies are not new here on Skeptoid. We run into them pretty routinely; and from what I've seen, they're usually a sort of shortcut detour from doing the extra work required to actually solve a mystery: "Strange glass-walled forts in Scotland? Ancient atomic blast. The ancients possessed modern superweapons. End of mystery."

Not only does that usually turn out to be factually wrong, it also deprives us of whatever the truly fascinating question is — and the answer, assuming we have one yet; and we don't always. But at least we learn what we don't know and why we don't yet know it.

So here's the way we should explore the mystery of the vitrified forts. I like to break it down into a four step process:

So let's begin with our first and most important question. Do vitrified forts exist, ancient stone walls with their sides melted into glass? This one's pretty easy to answer, because there's plenty of archaeological literature about them. Yes, they do exist, and the popularly given number of about sixty known examples in Scotland is correct. Some are small grassy lumps, hardly recognizable; some are large and exposed enough that visitors can walk right up and examine them. They're great, sloping piles of stone, often built on hilltops, and enclosing an area that we usually presume was to be defended. Timbers were often used to reinforce the walls from within, and from these timbers we've been able to get radiocarbon dating telling us when the forts were built. Most were built or repaired in various centuries during the first millennium BCE, around 700 to 300 BCE.

First, and most important, find out whether the observed mystery actually exists. Are there really ancient glassy forts across the Scottish countryside? And if there are, are they truly as reported?

Second, assuming we find that the vitrified forts do exist, check the archaeological literature and see what's known about them. See if the real experts have already answered these questions. How were they made? Why were they made?

Third is a step we take if the experts don't have a solution, which might well be the case. We look at the atomic blast conjecture. Are the forts truly consistent with that, and will we find any evidence to support the claim? Although this step can often seem silly, it's not at all. Think how cool it would be if that did turn out to be the case. Think of the neat stuff we'd learn about how to detect whether an atomic explosion happened somewhere. Think of the ramifications for our understanding of history.

Fourth and finally, we take an assessment and establish our provisional conclusion. It's entirely possible that we end up concluding the answer's not known. That's also a positive outcome, because it raises exciting possibilities for what the next steps should be.

The vitrification is not easy to spot. It doesn't look like glass; it looks like the native white rocks embedded in a sort of darker asphalt. Sometimes there are lava-like bubbles in the darker vitrified stone, and sometimes there are solidified drips; but without knowing what you're looking at, it's unimpressive visually. If you do know what you're looking at, it's really something else.

This brings us to our second step, finding out what's already known about the forts. When studying the vitrified forts, context is a crucial consideration. We must understand the technological context in which the forts were built. The first millennium BCE was smack dab in the middle of the British Iron Age, a historical era named after the smelting of ore into iron. Metalworking, forging, and vitrification were well known to the people of the age. It was not a mysterious technology. The melting of rocks to serve the purposes of mankind was the technological focus of the period. And even in this early date, it was not a new concept. The Iron Age was preceded by the Bronze Age. Mankind had been melting ore for perhaps 10,000 years, ever since (nobody really knows for certain) accidental discoveries were made in pottery kilns.

So when the archaeologists study the vitrified forts and report that we don't know how they were made, all we're saying is that we don't know exactly what method was used. We're not saying that it is a surprising or inexplicable accomplishment. Any number of methods could have been used; we just don't know which. The vitrified rocks require about 1100°C to vitrify in the observed manner. So let's take a quick look at what various researchers have discovered.

The most famous experiment, widely trumpeted in virtually all writings about the vitrified forts, was performed in 1934 and repeated in 1937 by Wallace Thorneycroft and Vere Gordon Childe who built a fire against an experimental stone wall, built to the observed specifications. As described in the 1966-67 edition of The Proceedings of the Society of Antiquaries of Scotland:

The experimental wall was 6 ft. wide and 6 ft. high, with horizontal timbers interlaced with stone slabs. After ignition through brushwood fires around the wall face, the wall began to burn and after three hours it collapsed. The core of basalt rubble became red hot, probably reaching 800 to 1200°C, and after excavation the bottom part of the rubble was found to be vitrified, with rock droplets and casts of timber preserved. The experiment proved that a timber-laced wall of this character could become vitrified through fire, but the explanation of the reasons for such widespread treatment of these Iron Age forts remains uncertain.

By that, they meant whether the vitrification was done deliberately by the builders, accidentally in a fire, or deliberately by attacking forces. Unfortunately this is an anthropological question, the certain answer to which is lost to history. Is it the result of an attack? Vitrification by attackers did not breach or destroy the walls, nor make them easier to scale. Builders may have done it on purpose; why, we don't know. It did not make the wall stronger or more difficult to breach. It was not always done; and even on most vitrified forts, it was usually done inconsistently in various patches. It could have been as simple as that the practice was traditional or ceremonial, or even merely aesthetic. We know it was done; we're just not sure why. All this suggests is that the reason is unknown, not that it was necessarily extraordinary.

Some evidence suggests that on a few forts, the vitrification was done from within the wall, during construction. Such walls were usually built with solid stone facings on the inner and outer sides, with rubble filling in the center. During construction, fires could have been built in the center of the wall, covered with turf for insulation, and allowed to vitrify the stone faces. Rubble could then be filled in, and construction would move up to the next level where the process would repeat. Other vitrified walls show evidence that the fire was built against the outside of the wall, as Thorneycroft and Childe did in their test. Keep in mind also that Thorneycroft and Childe were archaeologists with minimal stone melting skills, while the men who vitrified the forts two and a half millennia before them were expert professionals whose knowledge was based on centuries of experience.

It's important to keep in mind that wherever an Iron Age fortification was under construction, the supporting infrastructure of workers and local people would certainly have included blacksmiths, whose furnaces of the day reached some 1300°C. There was no lack for expertise in the arts of building smelting fires or keeping them hot.

And so without a complete explanation for the forts from archaeology, we proceed to step three, evaluation of the fringe conjecture that ancient atomic blasts were used to produce the vitrification. This suggestion is unnecessary. The temperatures required were well within the capabilities of the technology of the day, and have been repeated experimentally. And, of course, the elephant in the room is that atomic weapons were not available 2500 years ago — or, to be precisely scientific, not known to have been available. At the earliest experimental atomic blast, the Trinity test in 1945, the temperature reached 5.5 million Kelvins, 4,000 times hotter than what was needed to vitrify stone forts, and left blatantly obvious chemical signatures that nobody has yet reported finding at a vitrified fort site. This is all to say nothing of the virtually insurmountable task of rearranging practically all known human history to accommodate such a twist.

Some have also suggested that some variant of Greek fire may have caused the effect. Greek fire was an ancient weapon employed by the Byzantines about 1000 years later, but some sources have Athenians using something similar during the time of the vitrified forts. Although its exact composition is not known, Greek fire was probably simple petroleum collected from natural wells in the Middle East, useful in naval warfare for its ability to float on water while burning. Although vaguely plausible as an explanation, Greek fire would have been logistically difficult to transport such a great distance to serve a purpose that could have been served more easily by local wood, and likely would not have burned nearly hot enough nor long enough to vitrify the rock.

This brings us to our final step, assessing what we've learned, and establishing a provisional conclusion. Like all science-based conclusions, it's provisional because it's always subject to new information that may arise. We've learned that the technology required to create the vitrified forts was not extraordinary. Nothing found at the sites requires any re-examination of the history of knowledge. The questions that do remain are sociological. Why were the forts vitrified, and who vitrified them? I'm happy to report that we don't know yet, and that this is one more item to add to our list of mysteries still to be solved.

Brian Dunning

© 2012 Skeptoid Media, Inc. Copyright information

References & Further Reading

Childress, D. Lost Cities of Atlantis, Ancient Europe, & the Mediterranean. Stelle: Adventures Unlimited Press, 1995. 390-396.

Coles, J. "Experimental Archaeology." Proceedings of the Society of Antiquaries of Scotland. 1 Jan. 1966, Volume 99: 15.

Editors. "Vitrification of Hill Forts." Brigantes Nation. Brigantes Nation, 10 Aug. 2002. Web. 2 Sep. 2012. <http://www.brigantesnation.com/VitrifiedForts/VitrifieedForts.htm>

Maclagan, C. Hill Forts, Stone Circles, and Other Structural Remains of Ancient Scotland. Edinburgh: Edmonston and Douglas, 1875.

Thorneycroft, W., Childe, V. "The Experimental Production of the Phenomena Distinctive of Vitrified Forts." Proceedings of the Society of Antiquaries of Scotland.1 Jan. 1938, Volume 72: 44-55.

Williams, J. An Account of Some Remarkable Ancient Ruins. Edinburgh: William Creech, 1877.

Reference this article:
Dunning, B. "The Mystery of the Vitrified Forts." Skeptoid Podcast. Skeptoid Media, Inc., 4 Sep 2012. Web. 17 Oct 2013. <http://skeptoid.com/episodes/4326>

Discuss!

10 most recent comments | Show all 52 comments

[catfish]

i read it and the comments thanks ish

it still leaves lots of questions for me and i think the ancient atomic bomb theory is just silly .

ive read distracted`s post and im more confused than before cheers mate

im gonna look for more on this .

[distracted]

done my head in after the 3rd sentence ill try later when im awake more .

how about comet bits not acomet that went on to hit bolivia .

stories of a dragon in the sky that slit up into 7 pieces .

if objects from space dont melt rock why do we have glass in the desert ect .

just asking like

sorry mate, I am shit at explaining things, as you have just discovered

I'll try and explain what I mean a bit better.

Meteorites, comets, etc come in very fast, say 35,000+ mph, this vast speed and the weight of the object itself, transfers a massive amount of energy into the impact site when it hits.

Most rocks are made of crystals, and crystals are made of a mix of atoms all rigidly arranged in a scaffold like lattice. The vast pressure created as the super high speed object hits the surface squashes the rock, it squashes the crystals, it squashes the atoms in the lattice closer together.

As the pressure passes, the rock, crystals and the crystals lattice and everything that has been pressurised, rebounds in the opposite directions, but the pressure has been so high that the lattice of atoms stretches and breaks apart in the rebound, all the atoms become unattached to each other.

Loose atoms that aren't rigidly arranged anymore are nothing more than a liquid (at best) it can move like a liquid, act like a liquid but it hasn't become a liquid through heating as such, it can contain a lot of material that didn't fully collapse or collapse to liquid at all as the pressure missed them a bit, etc it is unique to impact events.

As the pressure wave went into the rock from a central point outwards, then the rebound, which is in the opposite direction heads towards the impact point and the unbound liquid bursts out from the surface and flies into the atmosphere

hope that makes better sense

Edited October 17, 2013 by distracted

[catfish]

@@distracted i think i get ya thanks for taking the time matey .

if an object(s) traveling in a line and crashing 1000s of km away

would say anything in that line be say be vaperized .....not that kind

could this cause rocks to vitrify?

[distracted]

if an object(s) traveling in a line and crashing 1000s of km away

would say anything in that line be say be vaperized .....not that kind

could this cause rocks to vitrify?

The impact site is the only place that rocks could vitrify, but around the impact site for upwards of 1000's of km (depending on the size of the impact) glass can be expected to fall, this falls as cooled lumps and balls called tektites and spherules, to smear onto something as liquid rock it would need to be close. As an object passes through the atmosphere, frictional heating emits IR but this isn't enough to affect the ground, even for the biggest impacts, where billions of tons of melted rock is reentering the earths atmosphere after being ejected into space,we could only at best raise the temperature to 3-400 degrees through IR radiation, 500 degrees less than most rocks would need

I don't think that you can explain vitrified hill forts at all using extraterrestrial impacts as the mechanism, landing sites for extraterrestrial spaceships would be harder to exclude than impacts. I would go with the burning of wood or other combustibles, deliberately as beacon fires, aesthetics, furnaces, funeral pyres, etc or through accident such as lightening igniting a fuel store