3,600 years ago, in a city sitting 11.3 km (7 mi) northeast of the Dead Sea in what is now Jordan, there was a town called Tall el-Hammam. In it, people were going about their daily lives. Some 22 km (14 mi) west of Tall el-Hammam lies the ancient walled city of Jericho, from biblical fame. There, too, did the people go about doing their own thing. Unbeknownst to them, their lives are in great peril.
Suddenly, something exploded near Tall el-Hammam. Anyone who was unfortunate enough to have had their eyes looking at the general direction of the explosion got themselves instantly blinded by the light it produced. The temperature of the air around suddenly felt hot—to the point of lethality, in fact. Anything combustible would have immediately caught on fire—woodworks, doors, weapons, and clothing were all suddenly lit aflame. Anything made of metal or clay would have immediately melted from the sheer heat of the surrounding air. In the blink of an eye, the entire city of Tall el-Hammam was on fire—and that wasn’t even the last of it.
Just a few seconds later, the unfortunate residents of this ill-fated town were blasted with very strong winds. Any building left standing in the flames would have immediately toppled. In fact, the four-storey palace inside the city lost its top 12 m (40 ft) from the winds, carrying the debris to the bottom of the nearby valley. Anyone or anything left alive by that point after the sudden heat spike would have been blasted away by the shockwave that followed it. In a span of a few seconds, the entire city of Tall el-Hammam was decimated. The very same winds that finished off Tall el-Hammam then reached Jericho, toppling some of its famous walls; some parts of Jericho burned as well.
This was the story painted by 15 years’ worth of excavations in the area, obtained by a team of scientists, researchers, and experts reaching hundreds of individuals—all to answer the crucial question of who—or what—was responsible for the destruction of this entire middle Bronze-Age city. Co-author Christopher Moore, an archaeologist and Special Projects Director of the Savannah River Archaeological Research Program and the South Carolina Institute for Archaeology and Anthropology, University of South Carolina, details their findings about the mysterious events that sealed the fate of Tall el-Hammam in the journal Scientific Reports and with the website The Conversation. Together with Moore on the project were: Philip Silvia, from Trinity Southwest University; Malcolm LeCompte, from Elizabeth City State University; and co-authors Allen West and Ted Bunch, among others.
Details in the Dirt
Years’ worth of excavations in the area revealed several key details about the site of Tall el-Hammam. For one, there seems to be a uniform layer of jumbled, burned items atop the site some 1.5 m (5 ft) thick. In it, researchers found fragments of charcoal, molten metal burned and molten clay and brick, and ash. This layer would be referred to by the team as the destruction layer. To them, it was evident that a great fire caused this damage—and the fire must have been hot enough to melt even clay pottery. The next question would then be what event, if any, could cause a fire hot enough to melt earthen pots.
It seems that, to the team, something from outside the Earth caused the fate of Tall el-Hammam. There were no nearby volcanoes for it to be caused by a volcanic eruption, A simple earthquake couldn’t have been capable of causing a fire so intense that it melts brick, either. To gather more evidence for their potential culprit, the research team sought help.
To answer this question, the team referred to an online calculator called the Earth Impact Effects Program, a project by creators Robert Marcus, H. Jay Melosh, and Gareth Collins, and a collaboration of Imperial College London and Purdue University. The website aims to estimate the “regional environmental consequences of an impact on Earth” through various parameters supplied by the user, such as the distance from the simulated impact, projectile size, and other parameters.
Entering parameters based on what information they had gathered from the site, the calculator churned out a possible culprit: an asteroid, small in size, that would have been similar to that which caused the Tunguska event of 1908. (The Tunguska event is said to have been caused by what would have been the largest asteroid to hit the Earth; the asteroid instead exploded in the skies above Russia, since it entered our atmosphere at an angle. The resulting explosion flattened close to 80 million trees in an uninhabited Siberian forest area.)
With a chase for the potential culprit now underway, Moore and the team needed to find the smoking gun.
Caught Red-Handed
The team closely examined the dirt and gravel scattered across the destruction layer of the Tall el-Hammam site. There, they found shocked quartz, which are fractured grains of sand that form when normal grains are exposed to exceedingly high pressures of up to 5 gigapascals (GPa), or about 725,000 psi. The destruction layer was also littered with tiny carbon structures known as nanodiamonds, which are tiny diamonds barely larger than some viruses. It seems that whatever it was that caused such a high-pressure, high-temperature event over the unfortunate city was enough to turn carbon material in its vicinity into very tiny diamonds.
Analysis of pottery fragments from the layer also revealed the presence of bubbles on their surfaces; these earthen pieces were simply solidified remnants of those that actually melted from the intense heat of the event, which may have reached temperatures of up to 1,500 °C (2,700 °F). The surfaces of these pottery fragments were also littered with embedded metallic grains of metals like iridium and platinum.
More evidence for the intense heat blast that passed over the city can be found in the scattered deposits of spherules, spherical particles of iron and sand that solidified soon after they were vaporized at around 1,590 °C (2,900 °F).
Evidence such as these have only been found at asteroid impact sites, such as the sites of the aforementioned Tunguska event, and the Chicxulub event which was responsible for wiping out the dinosaurs some 65 million years ago.\
Aftermath
The proposed asteroid that exploded over Tall el-Hammam may have also vaporized and ejected the nearby water from the Dead Sea over the area. Being highly toxic from the sheer amounts of salt in the water, the toxic water may have scattered across the lands from the impact; this, according to the research team, may be the reason why the city,together with some nearby settlements, remained uninhabited for hundreds of years after the proposed event took place. The resulting levels of salinity in the area would have been damaging for any crops they may have attempted to grow on the same soil, and would have needed hundreds of years’ worth of rain to wash out.
And so, with all the evidence gathered, Moore and team arrived at their identity of the culprit: an asteroid, similar in size to what caused the Tunguska event over Russia, traveling in the atmosphere at speeds of up to 61,000 km/h (38,000 mi/h). The asteroid exploded some 4 km (2.5 mi) above the skies of Tall el-Hammam. The resulting shockwave from the explosion must have sped along the land at about 1,200 km/h (740 mi/h), and the air temperature around the city shot up to 3,600 °C (2,000 °F). A minute later, that very same heated shockwave passed through Jericho some 22 km (14 mi) away, causing its famed walls to tumble and instantly causing fires within the walled city. Tall el-Hammam, however, would be decimated by the asteroid explosion. No one must have survived after the battering of both the shockwave and the intense heat. The site, along with nearby settlements, remained uninhabited for centuries after the explosion—partly due the increased salinity of the surrounding soil after the explosion scattered lakewater from the nearby, highly-saline Dead Sea.
The story of Tall el-Hammam remains as a reminder of what true dangers lie beyond our skies. Asteroids such as what may have caused this tragic chain of events are still around, flying about in the Solar System. Any single one of these asteroids could easily flatten a modern city, and anything around it. As such, it remains important for astronomers to monitor any near-Earth objects, such as asteroids and comets, that may come perilously close to our planet. The question is not “if” an asteroid will hit us; it’s “when.” And we must look into searching for answers for it before any space rock decides to pay a visit—lest we suffer a similar fate to the residents of Tall el-Hammam on that fateful day.
References
- Bunch, T. E., LeCompte, M. A., Adedeji, A. V., Wittke, J. H., Burleigh, T. D., Hermes, R. E., Mooney, C., Batchelor, D., Wolbach, W. S., Kathan, J., Kletetschka, G., Patterson, M. C. L., Swindel, E. C., Witwer, T., Howard, G. A., Mitra, S., Moore, C. R., Langworthy, K., Kennett, J. P., … Silvia, P. J. (2021). A tunguska sized airburst destroyed tall el-hammam a middle bronze age city in the jordan valley near the dead sea. Scientific Reports, 11(1), 18632. https://doi.org/10.1038/s41598-021-97778-3
- Earth impact effects program. (n.d.). Retrieved October 6, 2021, from https://impact.ese.ic.ac.uk/ImpactEarth/ImpactEffects/
- Kinzie, C. R., Hee, S. S. Q., Stich, A., Tague, K. A., Mercer, C., Razink, J. J., Kennett, D. J., DeCarli, P. S., Bunch, T. E., Wittke, J. H., Israde-Alcántara, I., Bischoff, J. L., Goodyear, A. C., Tankersley, K. B., Kimbel, D. R., Culleton, B. J., Erlandson, J. M., Stafford, T. W., Kloosterman, J. B., … Wolbach, W. S. (2014). Nanodiamond-rich layer across three continents consistent with major cosmic impact at 12,800 cal BP. Journal of Geology, 122(5), 475–506. https://doi.org/10.1086/677046
- Moore, C. R. (2021a, September 20). A giant space rock demolished an ancient Middle Eastern city and everyone in it – possibly inspiring the Biblical story of Sodom. The Conversation. http://theconversation.com/a-giant-space-rock-demolished-an-ancient-middle-eastern-city-and-everyone-in-it-possibly-inspiring-the-biblical-story-of-sodom-167678
- Moore, C. R. (2021b, September 21). Space rock that destroyed ancient city may have inspired biblical story of Sodom. Live Science. https://www.livescience.com/biblical-fireball-archaeological-evidence-jericho
- Redfern, S. (2013, June 27). Mystery solved: Meteorite caused Tunguska devastation. The Conversation. http://theconversation.com/mystery-solved-meteorite-caused-tunguska-devastation-15154
