Mount Vesuvius is one of the most dangerous volcanoes on earth. Its most famous eruption took place in 79 AD, when it covered the nearby town of Pompeii in several feet of volcanic ash. This eruption completely froze the entire city- and all its inhabitants- in time.
The volcanic ash that rained down upon Pompeii and the neighboring towns preserved the buildings, artifacts, and people almost perfectly. Today, we can walk through the streets of Pompeii, Herculaneum, and other nearby villas, and feel as though we’ve taken a step back in time.
It turns out that the volcanic ash from Vesuvius preserved the people of the area even better than experts thought. Recently, scientists found intact brain cells in the skull of a man killed by the volcano’s most famous eruption.
A Brief History of Mount Vesuvius
Mount Vesuvius has erupted more than fifty times, however, its most famous eruption took place in 79 AD. That eruption buried the ancient Roman city of Pompeii under a thick carpet of volcanic ash. It also buried several nearby villas, as well as other neighboring towns such as Herculaneum.
The eruption killed two thousand people, and destroyed the city. Pompeii and Herculaneum were then abandoned for nearly two thousand years.
A group of explorers found the city in 1748. They were amazed to find a nearly-intact city beneath a thick layer of dust and debris, with perfectly preserved household items scattered through the streets. Even more shocking, they discovered fully intact skeletons of the people who perished that fateful summer day .
Pompeii: The longest continuously excavated site in the world
Since its initial discovery, Pompeii has played host to thousands of archaeologists, scientists, and treasure hunters. Steven Ellis is a classics professor at the University of Cincinnati and the co-director of the Pompeii Archaeological Research Project: Porta Stabia. He says Pompeii is the longest continuously excavated site in the world.
“Because of this, what we find in Pompeii is that every step in the development in the science of archaeology was tested out in Pompeii—with mixed results,” he says .
Still today, one-third of Pompeii is underground. Experts, however, are in no rush to uncover it. Instead, the focus has been on preserving the portion of the city that has been excavated.
Over the last two hundred years, as archaeologists have slowly uncovered the city, it has no longer been protected by a layer of ash. This has exposed the ancient buildings to weather, pollution, and tourists, creating the risk of losing what was so perfectly preserved.
“As an archaeologist, I’m part of that process in the way that I document what gets dug out of the ground,” said Stanford University’s Gary Devore. “Since archaeology is destruction, we destroy bits of Pompeii as we go along. So it’s incredibly important that we record in great detail, with the ability to recreate what we’ve taken away afterward.” 
Intact Brain Cells
A team of researchers in Italy have recently found intact brain cells inside the skull of a young man who died during the Vesuvius explosion two thousand years ago. They found the cells while they were studying remains that archaeologists uncovered in the 1960s in Herculaneum.
Researchers believe the victim was about 25 years old when he died. They found him lying face down in a building that experts think the ancient people used to worship the god Augustus.
Pier Paolo Petrone is the lead researcher and a forensic anthropologist at the University of Naples Federico II. He said the project started when he noticed some glassy material shining from inside the skull .
Intact Brain Cells Caused by Vitrification
How can brain cells still be intact after two thousand years? It is due to a process called vitrification, which occurs in the presence of extreme heat.
“The brain exposed to the hot volcanic ash must first have liquefied and then immediately turned into a glassy material by the rapid cooling of the volcanic ash deposit,” explained Petrone .
Guido Giordano is a volcanologist who works at Roma Tre University who was also a part of the study. He said that by analysing the charred wood next to the skeleton, researchers concluded that the site reached a temperature of more than five hundred degrees celsius (932 degrees Fahrenheit).
Petrone says that these conditions preserved the brain cells with a resolution that is impossible to find anywhere else. They also found perfectly intact cells in the spinal cord.
“This opens up the room for studies of these ancient people that have never been possible,” Giordano added .
The team of researchers will be continuing to study the remains. They are a mixture of archaeologists, biologists, forensic scientists, neurogeneticists, and mathematicians from Naples, Milan, and Rome.
The goal of their studies is to learn more about the vitrification process. They want to learn the exact temperature the victims were exposed to, and how quickly the volcanic ash cooled. The team also plans on analysing proteins from the remains and their related genes.
How Does Ash Preserve Things So Well?
There are two reasons why volcanic ash does such a good job at preserving artifacts and fossils:
- It can bury whatever exists on land at the time of deposition without completely crushing or burning them. Dust storms can act in a similar way. The difference is they cannot create a thick enough deposit to bury all objects.
- Volcanic ash causes widespread death, but also provides the substance that preserves the bones of buried animals and humans. This is because water can seep through the ash. When this happens, the water reacts with glass shards and dissolves or replaces many of them with other elements. This either creates a void space or creates derivative minerals such as clay.
When it dissolves in water, excess silica can replace the soft materials that makeup bone. This creates an almost indestructible fossil, similar to petrified wood. These fossils can last for millions of years.
Will Vesuvius Erupt Again?
The last time Vesuvius erupted was in 1944, although it was not as catastrophic as the explosion that buried Pompeii. Experts do believe, however, that another eruption is due any day now. This could have unfathomable consequences since today nearly three million people live within twenty miles of the volcano’s crater .
Petrone says that this study is crucial if we want to be able to evaluate the risks in the event that the volcano erupts again .