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As the inhabitants of an ancient Middle Eastern city now called Tall el-Hammam one day went about their daily business around 3,600 years ago, they had no idea that an invisible icy space rock was heading towards them at around 38,000 mph (61,000 km / h).
Flashing in the atmosphere, the rock exploded into a huge fireball about 4 kilometers above the ground. The explosion was about 1,000 times more powerful than Hiroshima’s atomic bomb. The shocked townspeople who watched him were instantly blinded. Air temperatures rose rapidly above 3,600 degrees Fahrenheit (2,000 degrees Celsius). The clothes and the wood immediately caught fire. Swords, spears, mud bricks and pottery began to melt. Almost immediately the whole town was on fire.
Seconds later, a massive shock wave swept through the city. Traveling at around 740 mph (1,200 km / h), it was more powerful than the worst tornado on record. The deadly winds ravaged the city, demolishing all buildings. They sheared the top 40 feet (12 m) of the 4 story palace and blew the mixed debris into the next valley. None of the town’s 8,000 people or animals survived – their bodies were torn apart and their bones were blown into small fragments.
About a minute later, 22 km west of Tall el-Hammam, winds from the blast hit the biblical city of Jericho. The walls of Jericho collapsed and the city burned down.
It all feels like the climax of a Hollywood disaster movie at the edge of your seat. How do we know that all of this really happened near the Dead Sea in Jordan millennia ago?
It took almost 15 years of painstaking research by hundreds of people to get the answers. It also involved detailed analyzes of material excavated by more than two dozen scientists in 10 states in the United States, as well as Canada and the Czech Republic. When our group finally published the evidence recently in the journal Scientific Reports, the 21 co-authors included archaeologists, geologists, geochemists, geomorphologists, mineralogists, paleobotanists, sedimentologists, cosmic impact experts, and physicians. .
Here’s how we’ve built this image of devastation in the past.
Firestorm throughout the city
Years ago, when archaeologists examined the excavations of the ruined city, they were able to see a dark layer about 1.5m thick of charcoal, ash, melted mud bricks and of melted pottery. It was obvious that a violent firestorm had destroyed this city a long time ago. This dark band has been called the layer of destruction.
No one knew exactly what happened, but this layer was not caused by a volcano, earthquake, or war. None of them are capable of melting metal, mud bricks and pottery.
To understand what might, our group used the online impact calculator to model scenarios that match the evidence. Built by impact experts, this calculator allows researchers to estimate the many details of a cosmic impact event, based on known impact events and nuclear detonations.
It appears that the culprit in Tall el-Hammam was a small asteroid similar to the one that cut down 80 million trees in Tunguska, Russia, in 1908. It would have been a much smaller version of the giant boulder several kilometers wide. that pushed dinosaurs to extinction 65 million ago.
We had a probable culprit. Now we needed proof of what happened that day in Tall el-Hammam.
Find “diamonds” in the dirt
Our research revealed a remarkably wide range of evidence.
At the site, there are finely fractured grains of sand called shock quartz that only form at 725,000 pounds per square inch of pressure (5 gigapascals) – imagine six 68-ton Abrams military tanks stacked on your thumb.
The destruction layer also contains tiny diamonoids which, as the name suggests, are as hard as diamonds. Each is smaller than an influenza virus. It appears that the wood and plants in the area were instantly transformed into this diamond-like material by the pressures and high temperatures of the fireball.
Experiments with laboratory kilns have shown that the pottery and bubbling mud bricks in Tall el-Hammam liquefied at temperatures above 2,700 F (1,500 C). It’s hot enough to melt an automobile in minutes.
The destruction layer also contains tiny balls of molten material that are smaller than the airborne dust particles. Called spherules, they are made up of vaporized iron and sand that melt at around 2,900 F (1,590 C).
Additionally, the surfaces of pottery and molten glass are speckled with tiny molten metal grains, including iridium with a melting point of 4,435 F (2,466 C), platinum which melts at 3,215 F (1 768 C) and zirconium silicate at 2,800 F (1,540 F). VS).
Taken together, all of this evidence shows that temperatures in the city have risen more than those of the city’s normal volcanoes, wars and fires. The only natural process that remains is a cosmic impact.
The same evidence is found at known impact sites, such as Tunguska and the Chicxulub Crater, created by the asteroid that triggered the extinction of the dinosaurs.
A remaining puzzle is why the city and more than 100 other settlements in the region were abandoned for several centuries after this devastation. The high levels of salt deposited during the impact event may have made cultivation impossible. We’re not sure yet, but we believe the explosion may have vaporized or splashed toxic levels of Dead Sea saltwater across the valley. Without harvests, no one could live in the valley for up to 600 years, until the minimum rainfall in this desert climate washes away the salt from the fields.
Was there an eyewitness surviving the explosion?
It is possible that an oral description of the destruction of the city was handed down for generations until it was recorded as the biblical Sodom story. The Bible describes the devastation of an urban center near the Dead Sea – stones and fire fell from the sky, more than one city was destroyed, thick smoke rose from the fires and the inhabitants of the city were killed.
Could this be ancient eyewitness testimony? If so, the destruction of Tall el-Hammam could be the second oldest destruction of a human settlement by a cosmic impact event, after the village of Abu Hureyra in Syria around 12,800 years ago. Above all, it may be the first written record of such a catastrophic event.
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The frightening thing is that this certainly won’t be the last time a human city meets this fate.
Tunguska-sized aerial explosions, like the one in Tall el-Hammam, can devastate cities and entire regions, and they pose a serious modern danger. As of September 2021, there were over 26,000 known near-Earth asteroids and around 100 short-lived near-Earth comets. One will inevitably crash into Earth. Millions more remain undetected, and some may be heading towards Earth now.
Unless telescopes in orbit or on the ground detect these rogue objects, the world may not have any warning, as will the people of Tall el-Hammam.
This article was co-authored by research collaborators archaeologist Phil Silvia, geophysicist Allen West, geologist Ted Bunch and space physicist Malcolm LeCompte.
This article is republished from The Conversation, a nonprofit news site dedicated to sharing ideas from academic experts. It was written by: Christopher R. Moore, University of South Carolina.
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Christopher R. Moore does not work, consult, own stock or receive funding from any company or organization that would benefit from this article, and has not disclosed any relevant affiliation beyond his academic position. .
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