A young man killed in the 79AD eruption of Mount Vesuvius had his brains turned to glass in the extreme heat.
Forensic experts have examined the body of a 25-year-old Roman who died in the disaster, and discovered a shiny, solid black material inside his skull.
They say the mysterious substance is the remains of human brain tissue, which transformed into glass in a process known as “heat-induced brain vitrification”.
It’s the only known case of its kind, as brain tissue is rarely preserved for so long.
When it is found in the skulls of long-dead people, the tissue has normally turned to soap due to fatty acids.
“To date, vitrified remains of the brain have never been found,” said Dr Pier Paolo Petrone, a forensic anthropologist at the University of Naples Federico II.
Writing in the New England Journal of Medicine, Dr Petrone and colleagues say the “rapid rise in extreme heat” when Vesuvius erupted converted human tissue to glass.
The man whose brain was vitrified was found embalmed in ash in the 1960s, lying face-down on a bed in what was once the town of Herculaneum, which was destroyed in the devastating eruption.
Analysis of ancient wood at the site revealed the area got as hot as 520C during the disaster.
“This suggests extreme radiant heat was able to ignite body fat and vaporise soft tissues; a rapid drop in temperature followed,” the report says.
They believe the young man was asleep at the time and likely died instantly – a relief as the volcano’s pyroclastic flows (currents of very hot gas, ash and rock) would have caused his skull and bones to explode.
Previous studies by Dr Petrone and his colleagues suggested “surge temperatures” killed many of the inhabitants of Herculaneum, Pompeii and other Roman settlements, extreme thermal shock causing their internal organs to shut down.
The discovery of splatters of reddish iron compounds on the victims’ bones indicates their red blood cells burst when extreme temperatures vapourised their muscles and fat, the researchers say.
They’ve also suggested the victims’ brain fluid boiled in the heat causing their heads to explode, although other experts have expressed doubt about this particular finding.
The thermal energy released by Mt Vesuvius during the eruption was 100,000 times that of the nuclear bombings of Nagasaki and Hiroshima in 1945.