Millennia later, scientists believe they have figured out why – a dense cloud of carbon dioxide causes animals that breathe it to suffocate. Dating back 2,200 years, the cave was rediscovered by archaeologists from the University of Salento in 2011. Simulation image of Plutonium It was located in a city called Hierapolis in ancient Phrygia, in what is now Turkey, and was used for animal sacrifices, which were bulls led through Plutonium, or the Gate of Pluto, the ancient god of the underworld – by the purified priests. The purified priests are sacrificing bulls As the priests led the bulls in, people could sit on high chairs above and watch the smoke billowing from the gate killing the animals. “ This space was so full of fog and dense that one could hardly see the ground. Any animal that goes inside is met with instant death. I threw the sparrows in and they immediately took their last breath and fell. ” wrote the Greek historian Strabo (64 BC – 24 AD). A photo showing dead birds at the entrance to “Hell’s Gate” It was this phenomenon that alerted the archaeological team to the location of the cave. Birds flying too close to the mouth of the cave suffocated and fell – indicating that, thousands of years later, it is still as deadly as ever. The culprit is seismic activity underground, according to volcanologist Hardy Pfanz of the University of Duisburg-Essen in Germany, who led a study of the cave’s gas in 2018. A fissure runs deep inside. below the area emitting a large amount of volcanic carbon dioxide. Today’s Status of Plutonium The team measured carbon dioxide levels in the area connected to the cave, and found that the gas – slightly heavier than air – forms a layer 40 centimeters (15.75 inches) above the floor. They found that the gas is scattered by the Sun during the day, but it is most dangerous at dawn after a night of accumulation. Concentrations that reach above 50% at the bottom of the lake, about 35% at 10 cm, can even kill a person – but, above 40 cm, concentrations drop rapidly. During the day, there was still some carbon dioxide about 5 centimeters high, as evidenced by dead bugs found by the team on the floor of the site. And inside the cave, they estimate CO2 concentrations consistently range from 86 to 91 percent, as neither the Sun nor the wind can enter. An inscription at the site indicates the hell gods Pluto and Kore. (Francesco D’Andria / University of Salento) The team notes in their paper that there is a strong touristic element to the place. Tourists could purchase small animals and birds that they could throw down for sacrifice, and on holidays larger animals were sacrificed by priests. “While the bull was standing in the lake with its mouth and nostrils 60 to 90 cm high, the large, mature priests (galli) always stood upright in the lake, ‘ the team wrote in their 2018 paper. Spectators will see large, strong bulls that can’t stand the smoke for a few minutes, while the priests remain strong and proud – a testament to the power of the gods and priests to perform. present to the people at that time. However, researchers believe that the priests were well aware of the characteristics of the cave and surrounding arena, and were able to conduct major sacrifices at dawn or dusk in the early days. Quiet day for maximum effect. Current status of the area They may also burrow their heads inside or into caves during midday ceremonies to demonstrate their abilities, holding their breath to endure. But the presence of oil lamps also suggests that priests approached the cave at night, according to the researcher who found it, Francesco D’Andria. Currently, the ancient city of Hierapolis still becomes one of the attractions attracting thousands of tourists.

Submarine KRI Nanggala-402. Choking because of CO2 CNA quoted Mr. Clark – a naval expert – who used to be a submarine sailor – as CO2 accumulating in the KRI Nanggala-402 submarine can suffocate the crew even if they have not exhausted oxygen. “CO2 needs to be filtered out of the atmosphere with a chemical. But this chemical will soon run out. Oxygen can be produced by chemical candles. But CO2 will suffocate the crew before running out of oxygen. ” The power outage also affects the crew’s lifetime, Clark said. Electricity is needed to operate the CO2 absorber and the fan transfers air through the oxygen candle. The Indonesian lifeboat joins the search for the KRI Nanggala-402 submarine. Photo: AP Why the submarine lost power? Underwater submarines often depend on battery power, Clark said. And a breakdown in the battery compartment such as fire, explosion, flooding, etc. can cause a power failure. Meanwhile, Mr. Ben Ho – naval analyst said that a torpedo explosion could also cause the submarine to lose power. “Historically, major submarine accidents have often occurred due to technical problems or weapon explosions. Indonesian submarines went missing while torpedo shooting exercises. Maybe a torpedo exploded, ”said Mr. Ben Ho. Oil spills at the location where the submarine went down on the morning of April 21. Photo: AP Submarine locator If the submarine is intact, it can be “relatively easy” to be located using sensors, Clark said. Magnetic sensors, similar to mine detection systems, can detect the steel hull of a submarine. Sound sensors can show the sound from submarines. “But the area they need to look for is relatively large. The sensors can only be effective in a small area. Searching can take a long time. ” Mr. Ben Ho, meanwhile, said that even modern sonar equipment can hardly detect the wreck of a submarine if the seabed is rough. “The submarine’s nature is inherently difficult to detect. Submarine fleets are often referred to as silent soldiers, ”said Ho. If the submarine is truly trapped at a depth of 600 meters or less, the crew has a “near zero chance of survival,” said Ho. “The grim reality is that once the submarine exceeds its maximum depth, it will explode due to the enormous water pressure.” If this happens, the explosion will be picked up by a sensor in a nearby area, he added. Rescue process Once the submarine is found, Singapore’s MV Swift Rescue can begin its mission. MV Swift Rescue is the first ship in Southeast Asia capable of rescuing submarines. Singapore’s MV Swift Rescue train. Photo: Facebook The ship can operate at sea for four weeks before needing refueling. On board is a rescue cabin named Deep Search and Rescue Six (DSAR 6). Cabin is used to evacuate crew from submarines. However, Mr. Clark warned that the biggest challenge is the lying direction of the submarine in distress. “For example, if the submarine is on its side, the DSAR 6 will be difficult to reach.” Cabin DSAR 6. Photo: Facebook According to the naval news site Naval Technology DSAR 6 is 9.6m long and can reach a depth of 500m. It is operated by two crew members and can accommodate up to 17 people. When the DSAR 6 floats to the surface and is recovered by MV Swift Rescue, the submarine crew will be transferred to a recovery chamber for treatment. The cabin can accommodate up to 40 people. Singapore and Indonesia signed a cooperation agreement to assist with submarine rescue in 2012. The agreement allows the two countries to send resources and help each other if their submarines crash. The KRI Nanggala-402 submarine went missing on the morning of April 21 while participating in a torpedo drill near Bali. On board there are 53 people, including 49 sailors, a commander and three weapons specialists. The 1,395-ton KRI Nanggala-402 was built in Germany in 1977, and joined the Indonesian fleet in 1981. About 40 countries in the world have submarines, but only a few countries have the ability to rescue submarines.