Man's brain turned to glass after volcanic eruption, scientists think they know why

A young man’s remains from 79 AD have left experts speechless. His skeleton, found in the ancient town of Herculaneum, revealed something that no one expected. Fragments of his brain appear to have turned into shiny, black glass.

Volcanologist Guido Giordano, from the Department of Science at Roma Tre University, is part of a team that studied this strange phenomenon.

What exactly happened?

Archaeologists discovered the man during excavations in the 1960s, lying on a wooden bed in a building that was devoted to honoring Emperor Augustus. He was probably around 20 years old.

When nearby Mount Vesuvius erupted, waves of burning ash swept over Herculaneum. Researchers say that, at some point, the extreme heat transformed parts of his brain.

Understanding Mount Vesuvius – the basics

Mount Vesuvius is one of the most famous volcanoes in the world. It looms over the Bay of Naples in Italy, standing as both a breathtaking natural wonder and a ticking geological time bomb.

Back in 79 AD, the eruption that is the subject of this article buried the Roman cities of Pompeii and Herculaneum under thick layers of ash and lava, freezing them in time.

That eruption remains one of the deadliest in history, killing thousands and leaving behind eerily preserved ruins that give us a rare glimpse into ancient life.

Today, scientists keep a close eye on Vesuvius, since it’s still very much active and sits dangerously close to millions of people.

How the brain turned into glass

According to the new analysis, temperatures above 950°F (510°C) would have been needed. The tissue then had to cool fast enough to avoid crystallizing.

“This is an amazing and truly unexpected find,” exclaimed Giordano. Researchers point out that most organic matter would simply burn to ashes at this temperature.

Why it mattered for scientists

This unique case highlights a rarely seen effect of hot ash clouds, which are known as pyroclastic flows. Such clouds can blast into an area at high temperatures and then rapidly recede.

One reason the brain fragments remained is that the surrounding deposit was not hot enough to remelt the glass.

That deposit reached roughly 869°F (465°C), which is lower than the point where the glassy tissue would revert to a softer form.

Clues about a rare event

Researchers say that the first scorching surge struck Herculaneum minutes before the main flow arrived. That could explain how this man’s brain was briefly exposed to extreme heat but then cooled.

Complex neuron and spinal cord structures remained embedded in the hardened material. These delicate features rarely survive in such clarity.

Scientists examined the fragments with electron microscopes. They noticed patterns that align with known neuronal shapes, including axons.

Internal pores in the glassy chunks hinted at water vapor escaping from the tissue. The result was an almost volcanic obsidian-like appearance.

Why did this man’s brain turn to glass?

All other humans in Herculaneum at the time appear to have fled toward the sea. This man did not.

“Maybe he was drunk,” joked Giordano. He suspects the victim was simply overwhelmed by the sudden disaster.

Insights from a glass-preserved brain

Understanding how extreme heat affects human remains could help experts reconstruct events in ancient and modern disasters.

This case challenges previous assumptions about how bodies react in high-temperature environments.

It also raises questions about other potential instances of vitrified tissue that may have gone unnoticed in the past. If similar cases exist, they could provide further insights into the effects of pyroclastic flows on the human body.

Researchers may now look for evidence of this phenomenon at other volcanic sites where high heat and rapid cooling occurred.

Implications for volcanic hazards

Hot ash clouds can be extremely dangerous. Some modern fatalities, such as those near Guatemala’s Fuego volcano in 2018, likely involved these blasts.

Giordano explained that buildings near active volcanoes might need heat-resistant designs. Such measures could allow people a brief chance to escape.

Beyond a single discovery

Volcanic eruptions have shaped human history by burying entire cities. Pompeii is often in the spotlight, yet Herculaneum reveals equally gripping scenes.

The glass brain fragments remain the only known example of this natural process in human tissue. Their formation required fast heating, rapid cooling, and a precise window of temperature.

Insights on ancient life and death

Study co-authors believe the victim was part of a religious community. The building where he was found was dedicated to the worship of Augustus.

The exact details of his final moments might stay unknown. Still, his remains add a layer of understanding to what happened that deadly day.

The study is published in Scientific Reports.

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