The Science Behind Your Inexplicable Food Cravings

By Cody Cottier | August 6, 2019 4:04 pm
ice cream craving
(Credit: Nick Fewings/Unsplash)

You swallow your last bite of lunch and head back to your desk. A stack of papers awaits you, and you’re just easing into work mode when suddenly you’re ambushed by a sudden, inexplicable hankering for potato chips. Every trace of productivity vanishes from your mind, replaced by a fixation on that crisp, salty snack. But you just ate … you can’t be hungry already, right?

For decades, the popular narrative of “the wisdom of the body” held that our cravings are bodily signals meant to prod us into balancing actual nutritional deficiencies. But now the bulk of scientific evidence has largely struck down the notion —  how much nutritional value is there in a double-chocolate brownie, anyway? With a few exceptions (notably sodium deficiency, which can make even seawater seem appetizing), our yearnings are governed by our brains.

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Fecal Transplants: A Curious Cure in Human waste

By Kendall Powell | August 6, 2019 2:37 pm
(Credit: Artemida-psy/Shutterstock)

In 2008, gastroenterologist Colleen Kelly had a patient with a recurring and debilitating infection of the gut with a microbe called Clostridioides difficile. Nothing Kelly did could ease the woman’s severe abdominal cramping and diarrhea.

So Kelly — at her patient’s urging — decided to try something highly experimental: transplanting a fecal sample from a healthy donor into the large intestine. And it worked.

Kelly, of Brown University School of Medicine in Providence, Rhode Island, is now one of the leading doctors performing the procedure. She has done about 300 fecal transplants in the last decade, with good success — and has even, she says, seen ICU patients with the most severe form of the infection sit up and ask for food within a day of their transplant.

Today’s data show that fecal transplants cure 80 percent to 90 percent of patients with recurrent C. diff infections — and doctors across the globe have accepted them as a legitimate medical treatment. The procedure is considered experimental (no regulatory body in the world has officially approved it outside of investigational protocols), but hospitals now perform fecal transplants for up to 10,000 cases of recurrent C. diff infections per year in the US alone. OpenBiome, a nonprofit in Cambridge, Massachusetts, that collects and rigorously tests fecal donations from volunteers, has shipped more than 48,000 such samples in the last six years.

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CATEGORIZED UNDER: Health & Medicine, Top Posts

Meet Homo naledi: The Mysterious Human Cousin

By Bridget Alex | August 6, 2019 12:35 pm
homo naledi skeleton
A reconstructed Homo naledi skeleton made from the bones of multiple individuals. (Credit: Lee Roger Berger research team)

In 2013 a couple of spelunkers, caving 100 feet underground in South Africa, wriggled down a narrow vertical chute. They dropped into an uncharted chamber and in the flickers of their headlamps saw human-like bones scattered across the ground. It was a new species of hominin.

The fortuitous discovery in the Rising Star Cave system led to one of the most spectacular and puzzling fossil collections in paleoanthropology. The chamber contained more than 1,550 skeletal pieces belonging to at least 15 individuals from a previously unknown human ancestor, Homo naledi. Dated between 230,000 and 330,000 years ago, the species’ relatively recent age and odd amalgamation of traits changes our understanding of human evolution.

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CATEGORIZED UNDER: Living World, Top Posts

After You Die, These Genes Come to Life

By Kate Golembiewski | August 2, 2019 9:42 am
death genes
(Credit: Immersion Images/Shutterstock)

From the time we see Bambi’s mom bite the dust, we all know what death is. At least, we think we do. But the simple definition of death—that the body stops working—doesn’t take into account how weird our bodies actually are.

“We really know nothing about what happens when you die,” says Peter Noble, a former professor at the University of Alabama. Noble knows firsthand that surprises await scientists studying the end of life: he helped discover that long-dormant genes can spring into action hours or even days after an organism dies.

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CATEGORIZED UNDER: Health & Medicine, Top Posts
MORE ABOUT: genetics

Looking to Have a Lucid Dream? There’s a Pill for That

By Troy Farah | July 30, 2019 5:11 pm
Lucid Dreams
(Credit: Jakub Grygier/Shutterstock)

It’s possible to choose between being the captain or the co-pilot of your dreams. Lucid dreaming is a phenomenon that sees people taking control of the narrative of their dreams, often with thrilling results. Always wanted to fly? You can lift right off. Hungry for a giant cheeseburger? Dive right in.

Practitioners say that the technique requires discipline and patience to master. But there are also chemical shortcuts: supplements that seem to bring conscious control of the unconscious within reach for many. What’s more, the science behind these drugs says they likely work. However, unanswered questions about their safety and efficacy remain.

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CATEGORIZED UNDER: Mind & Brain, Top Posts

To Save the Internet, Silicon Valley is Sending it to Space

By Troy Farah | July 30, 2019 12:31 pm
Space Internet
The internet could one day reach every corner of the Earth courtesy of satellite constellations. (Credit: sdecoret/Shutterstock)

For decades, the basic principles governing how the Internet works have remained pretty much unchanged. But with massive growth on the horizon — thanks to everything from AI to blockchain, and from the 5G rollout to the ubiquitous Internet of Things — the amount of data we produce could eventually outpace physical storage capacity.

The solution? Look to space. That’s the bet companies like Amazon, Facebook, OneWeb, and other Silicon Valley darlings are wagering on. Elon Musk, CEO of SpaceX, is planning to carpet low-earth orbit with thousands of satellites that will bring low-latency internet to all corners of the globe. Amazon is betting on a similar so-called mega-constellation worth billions, while Facebook created PointView Tech, a subsidiary to develop their secretive Athena broadband satellite, which was granted FCC approval to begin experimental trials.

If we want to build factories on the moon or cities on Mars — or just keep up with current data growth trends — we’ll need a robust internet in space, these companies predict. And while networking operates very differently in zero gravity, the protocols it uses could actually be applied to terrestrial Wi-Fi as well. This symbiotic relationship may not only fix our issue with an overwhelming amount of data, it could reshape the internet itself.

Connectivity Problems

If you’ve ever experienced an outage while streaming Netflix, it’s likely due to the internet protocol suite on your home network. Technically known as TCP/IP, it works (roughly) this way: one computer sends info via a router to a second router, then to your home computer. But none of this data is saved on the routers. If there’s a disruption in the connection, the information is lost, and you get buffering in the middle of Black Mirror.

In space, this model simply won’t fly. The extreme distances and orbital variances make the TCP/IP system untenable. So, NASA scientists invented a new protocol in 1998 called Delay/Disruption Tolerant Networking, also known as the Bundle Protocol.

“I think mobile apps that need to transfer data in ‘spotty’ connectivity would benefit from the Bundle Protocol’s patience,” says Vint Cerf, a co-inventor of both TCP/IP in the ’60s and DTN in the ’90s. Cerf is known as “the father of the internet” and he sees not only terrestrial applications for DTN, but also views the protocol as the backbone of manned and robotic missions beyond Earth.

DTN works by sending data in bursts. This avoids errors and lags by storing information until the connection returns. And it prioritizes what it sends by importance, helping further reduce latency.

Another improvement is that DTN has integrity checks and encryption built in, unlike TCP/IP, making it a more secure form of internet. Considering the vulnerabilities of IoT devices — which are notoriously easy to hack — DTN promises to make the web more protected.

There are a few ways DTN is already being used. For example, reindeer herders in remote areas of Swedish Lapland don’t have reliable internet access. So, a team of computer scientists tested a network using DTN protocols, allowing the Saami herders to check email and cached websites and even track their reindeer flocks. Similar experiments have taken place in Antarctica.

The tactic has also been used several times in outer space. DTN was enlisted to control the Spirit and Opportunity rovers, launch a bomb at a comet and is even regularly used aboard the International Space Station. Despite that success, it hasn’t seen broad rollout for commercial applications. At least, not yet.

Interplanetary Broadband

On May 24, SpaceX launched its first test of 60 Starlink satellites as part of the company’s proposed mega-constellation of 12,000 small satellites. It promises to deliver high-speed, low-cost internet to every point on the globe. But Musk also sees it as an essential step toward putting humans on Mars — another long-term goal for SpaceX.

“We could use the Starlink structure and leverage it to put an internet system on Mars,” Musk told reporters at a symposium in Seattle in June. “We are going to need high bandwidth communications between Earth and Mars and the Starlink system will provide this.”

starlink satellites
Starlink’s 60 satellites prior to being released into orbit. (Credit: Official SpaceX Photos)

But the first Starlink deployment wasn’t without problems. The satellites caused light pollution that drew outrage from the astronomy community. Some complained that doubling the objects in Earth orbit could make it harder to see and study the heavens, and even further contribute to space junk. According to Business Insider, SpaceX lost contact with three of the satellites. They will gradually deorbit — burn up in Earth’s atmosphere — over the next year. But some say these issues will likely be worked out as the projects scale.

“I am not sure it is possible to speak of right or wrong at this point,” Cerf says. “Something like 60 nodes have been launched for what I understand to be evaluation purposes — a prudent move before putting up thousands of satellites. There are concerns from astronomers that they will have an effect on Earth-based optical and radio astronomy. The low-Earth orbits reduce latency significantly, making satellite and terrestrial networking more similar.”

Bridging the gap between internet in space and on the ground may not just be a good business prospect — it may be necessary for the survival of companies like Amazon. The mega-corporation is best known for selling toothpaste and USB sticks from warehouses, but it also sells online data storage known as cloud computing. A lot of it. According to The Verge, Amazon controls as much as 40 percent of the programs running in the entire cloud. That’s more than Google, Microsoft and IBM combined.

But to keep up with the massive demand for data, Amazon may eventually have to move their servers off-planet. Bezos has said his plans for going to space will mitigate climate change and “save the Earth.” He’s not just talking server farms in low-earth orbit, but entire factories.

SpaceX and Amazon’s plans are still in the very early stages, however. Meanwhile, several smaller companies like Swarm and LyteLoop are racing to beat the major players, offering different variations on data storage in space. But history has shown that this nascent industry is incredibly expensive and most companies have failed before they’ve gotten off the launch pad.

Take Teledesic, for example. The ’90s startup received millions of dollars from Microsoft chairman Bill Gates and a Saudi prince, among others, to deploy 288 broadband satellites built by Boeing. But that didn’t stop the $9 billion project from flunking in 2002. Around nine other efforts from that period also promised to “darken the skies” with spacecraft, eventually fizzling out. Could the new race for satellite internet be déjà vu?

“The space industry is basing a lot of its growth on DTN and the rise of mega-constellations,” says Christopher Newman, Professor of Space Law and Policy at Northumbria University in the United Kingdom. “The question is essentially an economic one: can the market sustain both cable providers and internet-from-space … In essence, satellite providers are moving heavily into the telecommunications market and the mega-constellations are all predicated upon the market being able to support this alternative method of data delivery.”

In other words, interplanetary internet is still bound by the rules of capitalism: If Starlink or Project Kuiper can’t make money, the projects will likely phase out, like earlier, failed experiments. In the meantime, we could still be searching for signal.

CATEGORIZED UNDER: Space & Physics, Technology, Top Posts
MORE ABOUT: Internet, satellites

If Wormholes Exist, Could We Really Travel Through Them?

By Bill Andrews | July 30, 2019 10:30 am
astronaut wormhole
Wormholes could offer a path to the most distant places in the universe. (Credit: dimonika/Shutterstock)

Wormholes make the best shortcuts in the universe. That’s true in a literal sense, since the theoretical things can connect distant corners of the cosmos (or even different universes), allowing a traveler to go someplace without having to visit everywhere in between.

But wormholes also present the perfect way for writers to get around that pesky speed of light, the universe’s speed limit and impediment to fast travel through the cosmos. If characters in science fiction aren’t taking months or years to travel between worlds, a wormhole is likely the reason.

Too bad, then, that as far as we know, the things don’t exist.

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CATEGORIZED UNDER: Space & Physics, Top Posts
MORE ABOUT: black holes

How Fireflies Glow — And What Their Signals Mean

Fireflies
The glow of fireflies on a summer night is actually a complex mating dance. (Credit: Shutterstock)

You might not really be sure you saw what you think you saw when the first one shows up. But you stare in the direction of the flicker of light and there it is again – the first firefly of the evening. If you are in good firefly habitat, soon there are dozens, or even hundreds, of the insects flying about, flashing their mysterious signals.

Fireflies – alternatively known as lightning bugs in much of the United States – are neither flies nor bugs. They’re soft-winged beetles, related to click beetles and others. The most dramatic aspect of their biology is that they can produce light; this ability in a living organism, called bioluminescence, is relatively rare.

I’m an entomologist who does research on, and teaches about, the ecology and biology of insects. Recently, I’ve been trying to understand the diversity and ecology of fireflies in my home state of North Carolina. Fireflies are found widely across North America, including many places in the west, but they are most abundant and diverse in the eastern half of the continent, from Florida to southern Canada.

Bioluminescent Beetles

A chemical reaction in the beetle’s abdomen gives it its bioluminescence. (Credit: Cathy Keifer/Shutterstock.com)

Fireflies produce light in special organs in their abdomens by combining a chemical called luciferin, enzymes called luciferases, oxygen and the fuel for cellular work, ATP. Entomologists think they control their flashing by regulating how much oxygen goes to their light-producing organs.

Fireflies probably originally evolved the ability to light up as a way to ward off predators, but now they mostly use this ability to find mates. Interestingly, not all fireflies produce light; there are several species that are day-flying and apparently rely on the odors of pheromones to find each other.

Each firefly species has its own signaling system. In most North American species, the males fly around at the right height, in the right habitat and at the right time of night for their species, and flash a signal unique to their kind. The females are sitting on the ground or in vegetation, watching for males. When a female sees one making her species’ signal – and doing it well – she flashes back with a species-appropriate flash of her own. Then the two reciprocally signal as the male flies down to her. If everything goes right, they mate.

A good example is Photinus pyralis, a common backyard species often called the Big Dipper. A male flies at dusk about 3 feet off the ground. Every five seconds or so, he makes a one-second flash as he flies in the shape of a “J.” The female Photinus pyralis sits in low vegetation. If she sees a fellow she likes, she waits two seconds before making a half second flash of her own at the third second.

Some species may “call” for many hours a night, while others flash for only 20 minutes or so right at dusk. Firefly light communication can get much more complicated; some species have multiple signaling systems, and some might use their light organs for other purposes.

While most male fireflies do their own thing and flash independently of other males of the same species, there are those that synchronize their flashes when there are many others around. In North America, the two most famous species that do this are the Photinus carolinus of the Appalachian Mountains, including in Great Smoky Mountains National Park, and the Photuris frontalis that light up places like Congaree National Park in South Carolina.

In both these species, scientists think the males synchronize so everyone has a chance to look for females, and for females to signal males. These displays are spectacular, and the crush of folks wanting to see them at the most famous locations has made it necessary to conduct a lottery for permission to view them. Both species, however, occur over wide geographic ranges, and it might be possible to see them in other, less congested places.

Stinky Chemical Defenses

Many fireflies protect themselves from predators with chemicals called lucibufagins. These are molecules the insects synthesize from other chemicals they eat in their diet. Lucibufagins are chemically very similar to the toxins toads exude on their skins, and while they are toxic in the right doses, they are also extremely distasteful.

Birds and other predators quickly learn to avoid fireflies. I’ve watched a toad on my back porch eat a firefly and promptly spit it back out; the insect walked away, gooey but apparently unharmed. A colleague of mine once put a firefly in his mouth – and his mouth went numb for an hour!

Mating Photinus pyralis. (Credit: Clyde Sorenson, CC BY-ND)

Many other insects visually mimic fireflies in order to reap the benefit of looking like something unpleasant to eat and poisonous. Fireflies appear to produce other defensive chemicals, too, some of which may contribute to their distinctive smell.

Many Photuris fireflies can’t manufacture these defensive chemicals. So the females of these big, long-legged lightning bugs do something surprising: Once they’ve mated, they start mimicking the flashes of female Photinus and then eat the males that respond. These femme fatales go on to use the lucibufagins they acquire from ingesting their severely disappointed prey to protect themselves and their eggs from predators. They quickly transfer the chemicals to their blood, and spontaneously bleed if a predator grabs them.

No Place Like Home

Most fireflies are habitat specialists, using woodlands, meadows and marshes. They rely on that habitat remaining undisturbed for the year or more it takes them to complete their lifecycles. These insects spend most of their lives as larvae preying on earthworms and other animals in the soil or leaf litter – most adults don’t feed at all. If that habitat is disrupted during their youth, populations can be extinguished.

Adding to this vulnerability is the fact that the females of many species – like the famous blue ghosts of the southern Appalachians and elsewhere – are wingless and can’t disperse any further than they can walk. If a population of blue ghosts is destroyed by logging or other disruption, there will be no reestablishment. Habitat destruction is therefore one of the greatest threats to fireflies. Other hazards include light pollution from artificial lights and perhaps insecticide applications for mosquito control.

There is much yet to learn about fireflies. Entomologists like me have identified about 170 or so species in North America, but it is clear that many more species occur here. Pay attention to the fireflies in your neighborhood; observe their flash patterns and behavior. Perhaps you’ll discover one of those new species.

The Conversation

This is a guest post from Clyde Sorenson, Professor of Entomology, North Carolina State University. This article reflects solely the views of the author.

This article is republished from The Conversation under a Creative Commons license. Read the original article.

CATEGORIZED UNDER: Living World, Top Posts

Probiotics Are Everywhere. Scientists Still Can’t Agree if They Actually Help

By Daniel Bastardo Blanco | July 26, 2019 2:39 pm
Human Microbiome
(Credit: T. L. Furrer/Shutterstock)

What if I told you that countless tiny beings living inside your body right now were responsible for everything from the health of your gut to your mental health? It sounds crazy. But, that’s exactly what research into the microbiome is showing us.

Tens of trillions of bacteria inhabit our bodies — scientists call them the human microbiome. The past decade or so has seen an explosion of studies linking gut bacteria with all sorts of diseases and conditions, from obesity to schizophrenia. The findings suggest managing our microbiome will help us stay healthy. And to do that, companies have encapsulated live bacteria in pills, called probiotics, that you can buy everywhere from Amazon to the local grocery store. But do they actually work or is all just hype?

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CATEGORIZED UNDER: Health & Medicine, Top Posts

These 4 Ancient Apocalypses Changed the Course of Civilization

By Paul Cooper | July 26, 2019 1:16 pm
Hekla Eruption
The eruption of the Icelandic volcano Hekla may have led to the collapse of multiple thriving Bronze Age societies. (Credit: Abraham Ortelius/Wikimedia Commons)

Life, as they say, goes on. Until one day it doesn’t. For ancient societies, without the means to predict natural disasters, destruction could often come suddenly and completely by surprise. Below are four of the most devastating natural events in recorded human history, and the societies that they wiped off the map.

The Storegga Slides

Until about 8,000 years ago, the British Isles were a peninsula, joined to mainland Europe by a strip of chalk downs, swamps, lakes and wooded hills. Today, we call this submerged world Doggerland.

Today, fishermen routinely bring up carved bone and antler tools from the Mesolithic hunter-gatherers who lived here. But by the end of the 7th millennium BC, a warming world caused sea levels to rise. The people of Doggerland must have watched with dread as their villages were swallowed up one by one. But one event would turn the slow advance of the sea into an apocalyptic terror.

The edge of the Norwegian continental shelf is an underwater cliff that runs for six hundred miles along the Atlantic Basin. And one autumn day around 6225–6170 BCE, this cliff collapsed. An estimated 770 cubic miles, or over 50 Mount Everests, of rock broke off and slid into the deep ocean. The rubble flow reached a speed of 90 mph underwater. 

Doggerland Map
A map showing the extent of Doggerland, along with the location of the Storegga slides. (Credit: Francis Lima/Wikimedia)

Meanwhile, on the surface, the ocean bent into a tsunami of unimaginable force. The waves may have reached initial heights of 260 feet, striking the Norwegian coast with 130 foot breakers, and Scotland with waves 65 feet high.

As for the people who lived in the low-lying fens of Doggerland, scientists believe this tsunami would have been catastrophic. A 16 foot wall of water buried settlements and farms beneath the waves. And there they would wait 8,000 years for the nets of fishermen to dredge up their remains.

Thera Eruption

During the mid-second millennium BC, one power dominated the Mediterranean. From their capital on Crete, the Minoans’ influence reached Cyprus, across the Greek islands and into modern Turkey and the Palestinian coast. They left behind remarkable paintings and pioneered technological advancements like indoor plumbing. They grew and flourished. That is, until one summer day around the year 1,600 BC.

The volcano of Thera, on what is now the Greek island of Santorini, erupted with the force of two million Hiroshima bombs. The destruction would have been virtually instant, eradicating all life on the island. Today, you can stand on top of cliffs 1,000 feet high that form the bowl of the Santorini crater, and imagine the vast tsunamis that rippled across the sea, the sky blackening overhead. Minoan settlements on nearby Crete were swept away.

The event devastated the maritime trade that was their lifeblood, and the Minoan empire all but collapsed overnight. In the centuries that followed, they would disappear entirely, even down to their name (the word “Minoan” is a Victorian invention). The eruption sent 24 cubic miles of rock into the atmosphere, four times more than the 1883 Krakatoa eruption. It blocked out the sun and threw the world into a period of bitter cold. Famines spread in Egypt as crops failed, and evidence of the eruption can even be found in the earliest Chinese written chronicles.

“At the time of King Chieh the sun was dimmed,” the records say. “Three suns appeared… Winter and summer came irregularly… Frosts in July.”

Santorini Crater
Santorini island, Greece, showing the caldera that is 12km across at its widest point. (Credit: EOS/NASA; Public Domain)

Thonis / Heraklion

Between the 6th and 2nd centuries BC, the Egyptian city of Thonis (known to the Greeks as Heraklion) was one of the busiest ports of the ancient world. Located on the shores of the Mediterranean, Thonis was the port through which olive oil, wine and copper flowed to the rich lands of the south, and gold, incense and papyrus spread north to the rest of the Mediterranean. It was the Venice of Egypt, a series of islands and sandbanks joined by bridges, pontoons and a grand canal connecting its two ports. Its towering buildings must have looked like they would last forever. But a rare phenomenon known as soil liquefaction would soon spell its doom.

The heavy buildings of Thonis were built on soft coastal ground made of clay. Loose, sandy soil of this kind, when saturated with water and struck by earthquake tremors, can undergo a sudden change that makes it behave like liquid. This is still a challenge to modern architects in earthquake-prone areas like Taiwan.

As earthquakes rocked the Mediterranean in the final centuries of the first millennium BC Thonis began to sink into the sea. Commerce stopped flowing into the city, and at the end of the 2nd Century BC, its grand temple to Amun collapsed. It seems the Egyptians tried to save their city: ancient shipwrecks discovered in the bay seem to have been scuppered intentionally as a measure against subsidence. By the 8th century AD, Thonis was completely swallowed by the waves, and only its name lived on.

The Hekla 3 Eruption

The Eastern Mediterranean at the end of the second millennium BC was thriving. Languages and cultures mingled here as trade routes criss-crossed land and sea, from Egypt and Greece to Turkey and the shores of Palestine. Markets bustled in the great thriving cities of Ugarit, Hattusha, Mycenae and Babylon, and the region saw a golden age of literacy and culture. But by 1,100 BC,  virtually every society in this part of the world would collapse, into ash and ruin. And the cause of all this destruction may have been over 2500 miles away, on the snowy slopes of Iceland.

Hekla Volcano
Hekla, the Icelandic volcano that some blame for the collapse of numerous civilizations at the end of the Bronze Age. (Credit: Hansueli Krapf/Wikimedia Commons)

Hekla is one of the world’s most active volcanos. It was thought to be the gate to hell, and the prison where the traitor Judas was tormented. And its most cataclysmic eruption in human history took place sometime around the year 1,100 BC, an event known as Hekla 3. It threw nearly two cubic milesof volcanic rock into the atmosphere, and kicked off a period of cooling that would last for years.

The rapid climate change that descended over northern Europe seems to have driven a vast number of refugees southward, placing unsustainable stresses on the region. The climate unrest caused several groups known as “The Sea Peoples” to begin raiding in the south, causing destruction and sacking cities. Under famine, rebellions and outside attacks, the interdependent societies of the Bronze Age collapsed like dominos, and a period known as “The Late Bronze Age Collapse” cast this whole region of the world into chaos.

Paul Cooper is also the host of the Fall of Civilizations podcast, streaming now.

CATEGORIZED UNDER: Environment, Living World, Top Posts
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