Researchers who examined the remains of a man whose brain was purported to have turned into glass when he was killed nearly 2,000 years ago in the volcanic eruption of Mount Vesuvius say they have figured out what caused the phenomenon.
The new findings, published Thursday in the journal Scientific Reports, shed light on what’s thought to be fossilized brain tissue formed by exposure to a rapid change in temperature.
Scientists have determined from spinal cord and skull samples that the victim, who was found face down in a bed buried under volcanic ash in Herculaneum, was exposed to temperatures exceeding 950°F, followed by quick cooling.
This process, known as vitrification, turned his brain tissue into a black, glassy substance — a rare phenomenon in organic materials.
“The process of transformation of anything liquid into glass is the fast cooling, not the fast heating,” volcanologist Guido Giordano told CNN.
While pyroclastic flows from Vesuvius reached only 869°F, researchers believe an ultra-hot ash cloud, capable of dissipating quickly, created the unique conditions needed for vitrification, according to the study.
The victim’s skull and spine likely protected the brain from complete destruction, allowing the glass to form.
To reach the findings, Giordano and his colleagues systematically cooled and heated fragments of the glass sampled from inside the skull and spine to understand the temperature extremes that caused the phenomenon.
The researchers found that the brain tissue transformed into glass at a temperature of at least 950°F.
“The ash cloud basically instantly killed the people, because they were engulfed in a cloud that was probably about 510, maybe 600 degrees (Celsius),” he added.
But not all scientists were sold on the study’s findings.
Forensic anthropologist Alexandra Morton-Hayward called the vitrification of soft tissue “incredibly unlikely,” according to CNN.
Morton-Hayward, a researcher at the University of Oxford who was not involved in the study, added that she was not convinced that the glassy substance was brain tissue.
Morton-Hayward has compiled a unique archive of information about 4,405 brains unearthed by archaeologists, according to the report.
Despite skepticism, lead researcher Guido Giordano maintains that the glass is organic, citing preserved neurons and proteins in the sample.
