Hierapolis, Turkey's mysterious 'portal to the underworld' | Hacker News Reader

Hierapolis, Turkey's mysterious 'portal to the underworld'

bbc.com

121 pointsbenbreen33 comments

Writers of the time, including Pliny the Elder and the Greek geographer Strabo, described these sacrifices as a chilling spectacle. A priest would lead an animal, perhaps a sheep or a bull, into the shrine. As if by the hand of the god, the animal would instantly drop dead, while the priest would walk out alive. "I threw in sparrows, and they immediately breathed their last and fell," wrote Strabo..

.."I wondered, could this Gate to Hell be a volcanic vent?".. "We saw dozens of dead creatures around the entrance: mice, sparrows, blackbirds, many beetles, wasps and other insects. So, we knew right away that the stories were true..."

.."When Pfanz tested the air around the vent with a portable gas analyser he discovered the reason: toxic levels of carbon dioxide. Normal air contains just 0.04% CO2 but Pfanz was shocked to discover that the concentration around the shrine reached a staggering 80%. "Just a few minutes exposure to 10% carbon dioxide can kill you," he said, "so the levels here are really deadly."

"These ultra-high levels of carbon dioxide are caused by the same geological system that created the area's hot springs and dramatic travertine terraces. Hierapolis is built on the Pamukkale fault, a 35km-long active tectonic fault zone where cracks in the Earth's crust allow mineral-rich water and deadly gases to escape to the surface. One of them runs directly under the city centre and into the Ploutonion."

"Almost certainly the choice of the Ploutonion's location was directly related to the seismic gas vents that exist here," said Yeomans. "Given that the underworld and the deities and myths associated with it were a significant part of their religious ethos, it makes sense that they would construct temples and shrines in places that most evoked the world that they believed lay beneath their feet."

"But such proximity to the forces of nature came at a price: an active fault zone also causes earthquakes, which levelled the city in 17 AD, 60 AD, and again in the 17th and 14th Centuries. Eventually, Hierapolis was abandoned."

There has also been speculation that mind altering gases inspired the prophecies of the Orcle at Delphi:

"Recent geological investigations have shown that gas emissions from a geologic chasm in the earth could have inspired the Delphic Oracle to "connect with the divine." Some researchers suggest the possibility that ethylene gas caused the Pythia's state of inspiration. Traces of ethylene have been found in the waters of the Castallian spring, which is now largely diverted for the town water supply of the town of modern Delphi. However, Lehoux argues^ that ethylene is "impossible" and benzene is "crucially underdetermined." Others argue instead that methane might have been the gas emitted from the chasm, or CO[2] and H[2]S, arguing that the chasm itself might have been a seismic ground rupture."[1]

[1] - https://en.wikipedia.org/wiki/Delphic_oracle#Fumes_and_vapor...

There is a very nice response to Lehoux et al. They apparently made serious errors in dismissing the ethylene hypothesis.

https://www.tandfonline.com/doi/full/10.1080/155636507014778...

According to Aristoxenus, Pythagoras attributed his doctrines to Themistoclea, the Pythia. Crediting a woman in 500BC! He would have seen the rebuilding of the oracle complex, too.

I can imagine being a priest/follower of Pluto, and finding an ancient cave that is unnaturally hot and with dead animals all around, dead because of non-apparent reasons and thinking that it could be a hallowed ground for the god of the underworld.

Truly, truly amazing.

I was just there; that whole region of Turkey (and Turkey in general) has really amazing and well preserved ancient artifacts and structures. I would definitely recommend the trip! My friend and I rented a car and just drove along the coast stopping at different museums, palaces, and ruins.

I always advise my friends interested in travel, "You'll find more of Ancient Greece in Turkey than in Greece"

The same goes for Ancient Armenia. I wonder why that is.

Could you mention the route you took. Interested in doing the same (versus the more conventional touristy version of Turkey)

What was the temperature and the weather like during this part of the year?

The 0.04% CO2 figure is from 420 parts per million, I'd imagine.

Anecdotally, I noticed that overly high (1000+) PPM numbers will make me drowsy and lethargic. IIRC, the mandated legal max for office buildings is 800; but it's easy to go way past that in a well-insulated home in the winter. There are sensors you can buy to monitor this figure so that you can open windows or move around when necessary.

Also, this figure was probably lower during when the stories took place.

Also, this figure was probably lower during when the stories took place.

Why? I would assume the opposite, if there were earthquakes in "17 AD, 60 AD, and again in the 17th and 14th Centuries" as the article states, I would guess that more gases were released when the area had higher seismic activity.

The background level of CO2 (not that of the caves themselves) was about 280 ppm in the Greek era: https://commons.wikimedia.org/wiki/File:CO2_40k.png

What a cool place. Ancient Greece has such a colored history.

they invented History ;)

Given that this is a heavily-trafficked tourist area, I can't help but suspect that the volcano researcher's discovery was likely already well-known to the locals. I mean, one would expect that CO2 concentrations of 80% in one place would cause a lot of animal deaths, not to mention be a severe health/safety threat to unwary tourists.

Oxygen is about 21% of the atmosphere in most places, so 80% CO2 doesn't seem very high (most of the atmosphere is CO2, but there's also other stuff in it albeit at much lower concentrations).

You probably wanted to say, most of the atmosphere is Nitrogen (~78%). 80% CO² would be quite interesting, effect-wise: https://pubmed.ncbi.nlm.nih.gov/31759856/

The atmosphere is about 78% nitrogen. Carbon dioxide forms about 0.04%

That doesn't mean that it isn't bad. From the article itself:

    Normal air contains just 0.04% CO2 but Pfanz was shocked to discover that the concentration around the shrine reached a staggering 80%. "Just a few minutes exposure to 10% carbon dioxide can kill you," he said, "so the levels here are really deadly."

> 80% CO2 doesn't seem very high

Are you a visitor from Venus? :) https://en.wikipedia.org/wiki/Atmosphere_of_Venus

Joke aside, as other posters say the CO2 concentration is more like 0.04% and even an increase for that is considered a contributing factor in global warming.

Its not just that a large concentration of CO2 dilutes oxygen- in high enough concentrations it can be toxic. 10% of athmospheric volume as CO2 is lethal in minutes- concebtrations over 30% are lethal in seconds, which is why in cases of CO2 poisoning at high concentrations victims will not appear to have been distressed- they quite simply did not have time to react. There are approximately 89 cases of CO2 poisoning in the US every year, about 2/3 of whom are themselves emergency rescue personell.

Update: I'm dumb and was thinking about nitrogen, thanks for the correction folks

must have felt so cool to solve an ancient mystery - second dream job for sure

Ok, I'll bite. What's the first?

racecar driver / AI professional obv.

Not cryo-frozen deep space explorer?

Ad click optimizer.

fuuuuuuuck that hahahah

Here have an upvote, because that was funny and you're new enough not to know being funny will get you downvotes.

Near to Hierapolis: https://www.tourmakerturkey.com/karahayit.html

this is sick

Not just sick. Deadly! Sacrificed to Pluto!

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