Science

Human brain turned to glass by ash cloud from Vesuvius

This piece of organic glass was found inside the brain of a man from ancient Rome who was killed in the Mount Vesuvius volcanic eruption
Pier Paolo Petrone
This piece of organic glass was found inside the brain of a man from ancient Rome who was killed in the Mount Vesuvius volcanic eruption
Pier Paolo Petrone

Excavations have found that the brain of what seems to be a human male contained dark glass formed during the eruption of Mount Vesuvius in 79 CE. The effect can't be explained by lava temperatures alone, but rather a different event from the cataclysm.

Even though Mount Vesuvius erupted nearly 2,000 years ago, excavation sites in areas affected by the massive volcanic eruption are continuing to reveal information about the event. In 2018 for example, archaeologists found the remains of a man who seemed to have survived the first phase of the eruption, only to be flung into the air with a giant block that crushed him as he fell.

Just last year, new excavations revealed the skeletons of two people who didn't die from the choking air or searing hot lava flows, but instead might be the first two ever found who died from the seismic activity accompanying the disaster.

Now a team of international researchers has unearthed a finding not only unique from the Vesuvius event, but in all of archaeology. The group found that the brain in a body killed in the eruption had turned to glass.

While you might first think the odd event happened because of the heat of the lava flows that accompanied Vesuvius' eruption, the researchers say they couldn't have been hot enough to cause the result. First of all, they say that temperatures related to the eruption would have topped out at about 465 °C (869 °F). That's too low for the 510 °C (950 °F) needed to turn body tissue to glass, and too high not to simply burn up the soft tissue.

Also, for glass to form naturally, some organic matter must liquefy and then cool quickly to prevent it from crystalizing as it becomes a solid. Not only were the pyroclastic flows too cool to cause this effect, they also would have cooled slowly over time, not quickly.

So, the researchers have theorized that a super-heated ash cloud that dissipated quickly was actually the first event in the Vesuvius cataclysm. This would have raised the dead man's temperature above 510 °C and, then after it dissipated, cooled the body quickly enough for the liquefied brain matter to turn to glass instead of crystalizing.

An image of the body at the excavation site
Guido Giordano et al/Scientific Reports

The remains studied by the researchers were found in the site of the ancient Roman town of Herculaneum, which was just about 17 km (about 11 miles) away from the more famous city of Pompeii. The remains likely belonged to a man of about 20 years-old who is believed to have been the guardian of the Collegium Augustalium, a building dedicated to the worship of Emperor Augustus. He was believed to have been lying in his bed when he succumbed to the ash cloud.

In determining that the obsidian-like glassy material they recovered from the site was indeed brain matter, the researchers exposed it to a series of chemical and imaging tests. Chemical analysis revealed a composition of human brain triglycerides and human hair fat, while a scanning electron microscope showed a well-preserved network of neurons, axons, and other neural structures.

"In conclusion, the brain tissue studied here is the only known case of preserved vitrification of human tissue as a result of cooling after heating to very high temperatures," write the researchers in a study published in the journal Scientific Reports. "This is the only way by which such a glass type can be preserved in the geological or archaeological record and explains why this is a unique occurrence and preserves the ultra-fine neural structure of the brain."

"Our findings have broad implications for material science, volcanology, forensic biology and archaeology," they add.

You can see the glass and learn more about the discovery in the following video.

Source: Springer Nature via Scimex

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1 comment
Malatrope
Why didn't the water in the skull flash into steam and explode it?