Science
Ancient Jordanian town destroyed by a meteor blast may have inspired Biblical stories, scientists say – CBC.ca
A thriving town in the Jordan River valley was utterly annihilated by the explosion of a meteor 3,600 years ago, which produced a flash and shock wave that scorched and shattered buildings, animals and people.
That’s the scenario painted by a large collaboration of archaeologists, earth and space scientists who have been studying the remains of the Bronze Age town at a site called Tall el-Hammam in Jordan, not far from the Dead Sea.
Before its destruction, Tall el-Hammam was a bustling town of perhaps 8,000 people, with mud-brick buildings and a four-story palace. There is evidence that the site of the town had been occupied for several thousand years.
Archaeologists have been excavating the ruins of the town for more than 15 years, revealing a rich history during its long occupation that included ruins from fires, warfare and earthquakes.
Their findings were published this month in the journal Scientific Reports.
The ‘destruction layer’
But their excavations also revealed destruction that didn’t have any ordinary explanation: a one-and-a-half-metre-thick layer of debris the team dubbed the “destruction layer,” encompassing the whole settlement, and dated to 1650 BC. This layer showed signs of an incredibly violent event.
It included melted pottery and bricks, soot, melted plaster and metal, that only could have resulted from temperatures approaching 2,000 C. It also contained ruins of flattened buildings, including the town’s palace and four metre-thick outer wall.
“The city was built with millions of mud bricks, in the walls, the ramparts, the buildings,” space physicist Malcolm LeCompte, who was part of the research team, told Quirks & Quarks host Bob McDonald. “Much of the mud brick was just disintegrated and blown away off the upper stories of these structures into the next valley.”
Most gruesomely, the debris also contained the remains of humans and animals that had been burned and torn apart.
“The human remains and bones were abundant. There’s very few total skeletal remains. Those that do remain are pretty disarticulated — just shattered,” said LeCompte. “It’s pretty horrifying, actually.”
The extreme temperatures and the widespread and violent destruction began to point the research team to a culprit. But microscopic examination of the debris also helped build the case. They found sand grains with unique cracks and fractures within them called “shocked quartz,” which are often found in the debris from super-high velocity impacts, like those generated by a meteor strike.
This led them to conclude that the best fit for what they were seeing was an “air burst” by meteor likely composed of rock and ice. The object, perhaps 50 metres across, would have hit the Earth’s atmosphere above the town travelling at perhaps 60,000 km/h. At that speed the atmosphere would have behaved as if it was almost solid, causing the meteor to explode violently.
“The evidence we have suggests that it was something like … a megaton-yield event in terms of its equivalent in atomic or nuclear bombs.” said LeCompte.
On the ground, the flash of heat from the explosion would have caused hair and textiles to burst into flame, and melted metal and brick. Moments later, a shock wave would have hit, causing winds that researchers estimate reached speeds of up to 1,200 km/h — knocking structures in the town flat and killing every living thing in the town.
“The shock wave would have come and just torn them apart,” said LeCompte.
It will happen again, LeCompte warns
The researchers point out that there are modern precedents for an event like this. In 1908 a similar-sized object is thought to have exploded in the atmosphere over Siberia, in what is known as the Tunguska event. It flattened 2,000 square kilometres of forest, and started a huge forest fire.
In 2013 a roughly 200-metre meteor exploded over Chelyabinsk in Russia, shattering windows and causing more than 1,000 injuries.
So far the team has found some material they think could be from the meteor, including tiny samples of rare metals often found in meteorites, but need to do more work to confirm their origin. LeCompte points out that excavation in the area can be difficult, particularly as much of the local landscape is currently occupied by Syrian refugees.
One intriguing, if speculative, possibility that the researchers have suggested is that the destruction of Tall el-Hammam might be the inspiration behind Biblical legends like the destruction of Sodom — in what is described as a “rain” of “fire and brimstone” — or the destruction of the walls of Jericho.
But LeCompte says those that look at Tall el-Hammam as a historical curiosity are missing the point. Instead, he said, they should look at it as a warning.
“The significance to its past pales in what it foretells for the future, because this is going to happen again,” he said. The Tunguska event shows that the Earth can still be struck by destructive objects from space, and if something similar were to happen over a city or populated region, the devastation would be enormous.
“It just took it out in an instant, so that’s a serious warning of what could happen — what will happen — in the future.”
Written by Jim Lebans. Produced by Mark Crawley.
Science
Ancient plankton migration offers clues to future marine extinctions – Open Access Government
Researchers reveal new insights into how marine communities responded to extreme global warming events millions of years ago and how that informs our research today
The research teams from the University of Bristol, Harvard University, the University of Texas Institute for Geophysics, and the University of Victoria look at the potential impact of current and future climate change on marine ecosystems.
Past climate events
The research focused on the Early Eocene Climatic Optimum, a period about 66 million years ago known for its exceptionally high global temperatures, similar to the most severe global warming scenarios predicted today.
During this time, marine organisms, particularly plankton, faced unusual heat stress. The findings suggest that most marine communities, except for highly specialised species, migrated towards cooler regions to escape the tropical heat.
Dr Adam Woodhouse from the University of Bristol’s School of Earth Sciences, who led the study, explained the significance of these discoveries: “We knew that biodiversity amongst marine plankton groups has changed throughout the last 66 million years, but no one had ever explored it on a global, spatial, scale through the lens of a single database.”
Using the past to predict the future
The team used the Triton dataset developed by Dr. Woodhouse during his PhD to analyse global biodiversity changes over millions of years. By applying innovative network analysis techniques to micropalaeontology, they reconstructed global spatial changes in marine community structures across the Cenozoic era.
“The fossil record of marine plankton is the most complete and extensive archive of ancient biological changes available to science,” noted Dr. Woodhouse. “By applying advanced computational analyses to this archive we were able to detail the global community structure of the oceans since the death of the dinosaurs, revealing that community change often precedes the extinction of organisms.”
This study will hold importance for modern marine ecosystems; it is important to continue monitoring and researching. By using the new data, it will be easier to predict the impacts of climate change on marine biodiversity.
By expanding the research to other marine groups and incorporating new models, the team aims to use historical patterns to predict future changes in marine community structures under different warming scenarios.
Understanding how marine communities responded to ancient climate extremes provides insights into the resilience and vulnerability of modern ecosystems.
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Science
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Quirks and Quarks54:00Why this Indigenous researcher thinks we can do science differently, and more…
On this episode of Quirks & Quarks with Bob McDonald:
This researcher wants a new particle accelerator to use before she’s dead
Quirks and Quarks9:05This researcher wants a new particle accelerator to use before she’s dead
Physicists exploring the nature of reality need ever more capable particle colliders, so they’re exploring a successor to the Large Hadron Collider in Europe. But that new machine is at least decades away. Tova Holmes, an assistant professor at the University of Tennessee, Knoxville, is one of the physicists calling for a different kind of collider that can come online before the end of her career – or her life. This device would use a particle not typically used in particle accelerators: the muon.
Is venting the best way to deal with anger? The scientist says chill out.
Quirks and Quarks6:51Is venting the best way to deal with anger? The scientist says chill out
It turns out that acting out your anger might not be the best way to get rid of it. Sophie Kjaervik, a researcher at Virginia Commonwealth University in Richmond, Va., analyzed 154 studies of the different ways to deal with anger. Her results, published in the journal Clinical Psychology Review, suggest that techniques that reduce your heart rate and calm your mind are more effective than blowing off steam.
High intensity wildfires may release toxic forms of metals
Quirks and Quarks8:37High intensity wildfires may release toxic forms of metals
Wildfire smoke might be more dangerous than you think. A recent study in the journal Nature Communications found that when wildfires pass over soils or rocks rich in a normally harmless metal called chromium, it is transformed into a toxic form. The hotter and more intense the wildfire is, the more of this metal becomes toxic. Scott Fendorf, an Earth system science professor at Stanford University, said this study shows we should factor in the type of geology wildfires pass over to provide more targeted air quality warnings about smoke risks.
AI might help solve the problem of runaway conspiracy theories
Quirks and Quarks7:35AI might help solve the problem of runaway conspiracy theories
Conspiracy theories seem to have multiplied in the internet era and so far, we haven’t had much luck in debunking these beliefs. The preliminary findings of a new study on PsyArXiv, a site for psychology studies that have yet to be peer-reviewed, suggests that artificial intelligence may have more success. Thomas Costello, a postdoctoral psychology researcher at MIT was the lead author on this study, and said their findings can provide a window into how to better debunk conspiracy beliefs.
An Indigenous scientist explores the medicine the Earth needs
Quirks and Quarks19:12An Indigenous ecologist on why we need to stop and listen to save the planet
Earth day is April 22. And Earth is not in great shape to celebrate the day. Overheated, overpopulated, overexploited – we’re not being particularly careful with our planet. We talk to Indigenous ecologist Jennifer Grenz of the University of British Columbia about her new book, which is part memoir, part prescription for the medicine our planet needs – a compound of science and traditional wisdom. Her book is Medicine Wheel for the Planet: A journey toward personal and ecological healing.
READ MORE: An Indigenous ecologist on why we need to stop and listen to save the planet
In a remarkable development, NASA has given the green light to the Dragonfly mission, a revolutionary rotorcraft designed to investigate the complex chemistry of Saturn‘s moon Titan.
This confirmation allows the mission to proceed with the final design, construction, and testing of the spacecraft and its scientific instruments.
Deciphering the prebiotic chemistry on Titan
The Dragonfly mission, led by Dr. Melissa Trainer of NASA’s Goddard Space Flight Center, will carry a cutting-edge instrument called the Dragonfly Mass Spectrometer (DraMS).
This powerful tool will help scientists delve into the intricate chemistry at work on Titan, potentially shedding light on the chemical processes that led to the emergence of life on Earth, known as prebiotic chemistry.
“We want to know if the type of chemistry that could be important for early pre-biochemical systems on Earth is taking place on Titan,” explains Dr. Trainer, a planetary scientist and astrobiologist specializing in Titan.
Titan: Dragonfly’s target
Titan, the largest moon of Saturn, is shrouded in a dense nitrogen-rich atmosphere, bears a striking resemblance to Earth in many ways. With a diameter of 5,150 kilometers, Titan is the second-largest moon in our solar system, surpassed only by Jupiter’s Ganymede.
Dense atmosphere and unique climate
One of Titan’s most distinctive features is its thick atmosphere, which is composed primarily of nitrogen and methane. This dense atmosphere creates a surface pressure 1.5 times higher than Earth’s, making it the only moon in our solar system with a substantial atmosphere.
The presence of methane in Titan’s atmosphere leads to a fascinating hydrological cycle, similar to Earth’s water cycle, but with methane as the primary liquid.
Titan’s surface is dotted with numerous lakes and seas of liquid hydrocarbons, predominantly methane and ethane. These liquid bodies, some of which are larger than the Great Lakes on Earth, are the result of Titan’s unique climate and atmospheric conditions.
The Cassini mission, which explored the Saturn system from 2004 to 2017, provided stunning images and data of these extraterrestrial lakes and seas.
Dragonfly mission to search Titan for prebiotic chemistry and life
The complex chemistry occurring on Titan’s surface and in its atmosphere has drawn significant attention from astrobiologists.
With its abundant organic compounds and the presence of liquid methane, Titan is considered a prime candidate for studying prebiotic chemistry and the potential for life to emerge in environments different from Earth.
Beneath Titan’s icy crust lies another intriguing feature: a global subsurface ocean of liquid water and ammonia. This ocean, which is believed to be salty and have a high pH, may potentially host microbial life.
The presence of this subsurface ocean, along with the unique chemistry on Titan’s surface, makes this moon a fascinating target for future exploration and scientific research.
Pushing the boundaries of rotorcraft exploration
Nicky Fox, associate administrator of the Science Mission Directorate at NASA Headquarters, emphasized the significance of the Dragonfly mission, stating, “Exploring Titan will push the boundaries of what we can do with rotorcraft outside of Earth.”
Titan’s unique characteristics, including its abundant complex carbon-rich chemistry, interior ocean, and past presence of liquid water on the surface, make it an ideal destination for studying prebiotic chemical processes and the potential habitability of an extraterrestrial environment.
Innovative design and cutting-edge technology
The Dragonfly robotic rotorcraft will leverage Titan’s low gravity and dense atmosphere to fly between different points of interest on the moon’s surface, spanning several miles apart.
This innovative approach allows the entire suite of instruments to be relocated to new sites once the previous one has been thoroughly explored, providing access to samples from diverse geological environments.
DraMS, developed by the same team responsible for the Sample Analysis at Mars (SAM) instrument suite aboard the Curiosity rover, will analyze surface samples using techniques tested on Mars.
Dr. Trainer emphasized the benefits of this heritage, stating, “This design has given us an instrument that’s very flexible, that can adapt to the different types of surface samples.”
Dragonfly mission challenges and funding
The Dragonfly mission successfully passed its Preliminary Design Review in early 2023. However, due to funding constraints, the mission was asked to develop an updated budget and schedule.
The revised plan, presented and conditionally approved in November 2023, hinged on the outcome of the fiscal year 2025 budget process.
With the release of the president’s fiscal year 2025 budget request, Dragonfly is now confirmed with a total lifecycle cost of $3.35 billion and a launch date set for July 2028.
This reflects a cost increase of approximately two times the initially proposed cost and a delay of more than two years from the original selection in 2019.
Despite the challenges posed by funding constraints, the COVID-19 pandemic, supply chain issues, and an in-depth design iteration, NASA remains committed to the Dragonfly mission.
Additional funding has been provided for a heavy-lift launch vehicle to shorten the mission’s cruise phase and compensate for the delayed arrival at Titan.
Rigorous testing and validation
To ensure the success of the Dragonfly mission, researchers on Earth have conducted extensive testing and validation of the designs and models for the nuclear-powered, car-sized drone.
The mission team has carried out test campaigns at NASA’s Langley Research Center, utilizing the Subsonic Tunnel and the Transonic Dynamics Tunnel (TDT) to validate computational fluid dynamics models and gather data under simulated Titan atmospheric conditions.
Ken Hibbard, Dragonfly mission systems engineer at APL, emphasized the importance of these tests, stating, “All of these tests feed into our Dragonfly Titan simulations and performance predictions.”
As the Dragonfly mission progresses, it marks a new era of exploration and scientific discovery. Dr. Trainer expressed her excitement, saying, “Dragonfly is a spectacular science mission with broad community interest, and we are excited to take the next steps on this mission.”
Turning science fiction into fact with the Dragonfly mission
In summary, the Dragonfly mission embodies the essence of human curiosity and the relentless pursuit of knowledge. As NASA prepares to send this revolutionary rotorcraft to the alien world of Titan, we stand on the brink of a new era of exploration and discovery.
With its innovative design, cutting-edge technology, and the unwavering dedication of the mission team, Dragonfly will unlock the secrets of prebiotic chemistry and shed light on the potential for life beyond Earth.
As we eagerly await the launch of this titanic mission, we can only imagine the wonders that await us on Saturn’s enigmatic moon. The Dragonfly mission is a testament to the indomitable human spirit and our boundless capacity to push the frontiers of knowledge.
In the words of Ken Hibbard, “With Dragonfly, we’re turning science fiction into exploration fact,” and that fact will undoubtedly inspire generations to come.
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