Episodi
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In October 1964, three young thieves cased the American Museum of Natural History in New York City.
They returned that night to scale the museum wall, climb through a bathroom window, and steal 22 of the most precious jewels in the world.
Among them were the Eagle Diamond, the DeLong Star Ruby, and, most famous of all, the Star of India sapphire.
Sapphires are a variety of corundum, the third-hardest mineral. Pure corundum is clear, but when colored blue by titanium impurities, it’s called a sapphire. When colored red by chromium, it’s a ruby.
Mineral inclusions in a sapphire sometimes line up along its crystal lattice to reflect light in a six-pointed star.
The Star of India, besides being huge and nearly flawless, has stars that are visible from top and bottom.
The thieves didn’t go far with it, renting a luxury apartment near the museum.
An informant tipped off the police, who raided the place and captured one of them.
The other two fled to Florida; the cops pursued and, a few days later, apprehended them, too—but not before they dispersed the jewels.
The Eagle Diamond was never recovered, probably cut into several smaller stones.
The philanthropist John D. MacArthur, paid a ransom to have the DeLong Ruby returned to the museum.
One of the thieves finally led detectives to the Star of India, which they found with several smaller gems in a wet leather bag in a bus-station locker.
It’s Earth’s near-flawless creations that humans still value the most… -
If you’ve been to Iceland, you know it doesn’t have much ice. In fact, there’s so much grass that on maps it’s colored green.
On the other hand, you probably know that Greenland is covered in glaciers. So why is the green one Iceland and the white one Greenland?
Legend has it that the Vikings who discovered Iceland wanted to protect it from settlement, so gave it an unflattering name.
But it was actually a matter of perspective. The first explorer to Iceland had a terrible trip. His daughter died on the long voyage. He arrived in winter and his livestock froze. That spring, his ship was nearly sunk by icebergs.
Fed up, he called it as he saw it: Iceland. And the name stuck.
A century later, another Viking explorer was visiting Iceland when he got in a fight with the settlers and was run off the island.
He sailed west and found Greenland, which was warmer than today, and the coastal areas were indeed green. Wanting to attract settlers, he called it Greenland.
They came, and built farms and grazing operations—which lasted until around 1400, when the climate cooled.
Greenland’s glaciers expanded, leaving less green land.
Today the Arctic is warming, which means Greenland’s glaciers are melting, and it may one day be greener again.
Conversely, cold glacial meltwater entering the ocean from Greenland could blunt the Gulf Stream that warms Iceland, making it icier. -
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We often think that evolution takes thousands of years. But in rare cases where humans impact small populations, adaptation can work much faster. Take the case of the tuskless elephant.
Nearly all male elephants and most females have tusks. These are just elongated lateral incisors that grow outward once the elephant loses its baby teeth.
But a small percentage of elephants are born without these teeth and never develop tusks.
In 1919, the South African government brought trophy hunters to the East Cape to exterminate elephants that were eating crops and trampling farms.
By 1931, only eight females survived, and half were tuskless—perhaps because they made the least attractive trophies. Instead of natural selection, this was human selection.
Fortunately, public opinion forced a change of heart and a preserve was established to protect the elephants.
The tuskless matriarchs had tuskless offspring, and today nearly all female elephants in the park lack tusks.
A similar thing happened in Mozambique. During a 15-year civil war, soldiers poached elephants for their meat to feed the troops and for their ivory to sell to buy more weapons.
Again, elephants with tusks were killed, and by the end of the war, half the females were tuskless. As the population has rebounded, a large portion of females remain without tusks.
But with the hunting pressure off, experts think natural selection may again favor animals with tusks—and both groups may eventually become tusked again. -
This 4th of July, try regaling your fellow revelers with some firework history and, yes, geology.
They’ll probably know that fireworks originated in China. But they likely won’t know they started as simple bamboo sticks thrown into a fire.
The air inside the hollow stalks expanded, then exploded, making a “crack” that the ancient Chinese used to ward off evil spirits.
A few centuries later, legend has it that a kitchen recipe gone awry combined charcoal, saltpeter, and sulfur. Who knows what food they were trying to make…but they created gunpowder.
Warlords quickly recognized its military potential. Luckily, firecracker enthusiasts pursued its celebration potential.
They filled those same bamboo tubes with gunpowder, to make a far bigger noise, then used more gunpowder to launch ever-larger firecrackers into the air. And fireworks were born.
When Marco Polo came to China, he was so impressed that he took fireworks back to Italy, where they’ve been a hit for over 700 years.
The Italians were the first to add common minerals like gypsum and calcite to produce colored explosions.
The science has come a long way since, now blending in a variety of metal salts and exotic minerals to make better fuels and to add deeper colors and special effects.
So when you see a brilliant finale of red, white, and blue, you can shout, “Wow! Celestine, barium oxide, and copper ore!”
Then you can blame EarthDate for making you the science nerd at the party. -
Leonardo da Vinci once said: “We know more about the movement of celestial bodies than about the soil underfoot.”
He was right 500 years ago, and he’s still right today.
That’s partly because the study of space is mysterious and cool, and there really wasn’t much interest in studying dirt. Until recently...
We now know that about 90 percent of all land-based species live in the soil, not on it. Most of these are microscopic, but they’re incredibly plentiful: there are more microbes in a handful of dirt than people on the planet.
And they’re also incredibly important: without soil microbes, plants might not exist.
Plants require nitrogen and other trace elements, and it’s soil bacteria, and the single-celled organisms that eat them, that process these elements into forms that the plants can use.
With this knowledge, agricultural researchers are reintroducing bacteria into depleted soils to increase the health and nutrition of crops.
Most plants also depend on soil fungi, and this relationship is symbiotic.
The fungi penetrate or encase the roots of plants to draw out what they can’t make themselves: sugars from photosynthesis.
In exchange, the fungus filaments stretch deep into the soil, gathering water and nutrients from a volume 100 times greater than the roots could reach on their own.
This fungal network can even join plants together beneath the soil, which allows amazing things to happen—and we’ll talk more about that on another EarthDate. -
We talked about how a fungal network connects plants underground. But did you know it allows them to communicate?
Specifically, they exchange sugars, and chemical and electrical signals, with each other.
The largest trees are now known to “mother” the surrounding forest. They give their sugars back to the entire soil community, to support neighboring plants and trees.
They’ve even been shown to preferentially identify young trees within their own species, and send them a larger serving of sugars via the fungal network.
And, plants and trees have learned to communicate through the air.
Many studies have shown that, when attacked by insects or disease, they release distress hormones to other plants, as well as defensive compounds.
Pine trees, for instance, when preyed on by caterpillars, send out pheromones that attract wasps to the forest, which prey on the caterpillars.
Acacia trees, when eaten by grazing giraffes, release ethylene gas, which prompts other acacias to flood their leaves with bitter tannins. Giraffes have learned to graze downwind...
Traditional lumber practices have removed large trees, with the idea that it allows other trees to access their sunlight. This new research may require rethinking how we maintain healthy forests.
This isn’t to say that trees can think—at least not in the way that humans define sentience.
But they certainly have a type of language that has allowed them to thrive for millions of years. We’re only now learning to understand it. -
If you’re driving while listening to this, please think of your vehicle not as a mere car or SUV, but as a starship cruiser!
Here’s why: the iron it’s made of came from the heart of a distant star.
Stars begin their lives as giant balls of gas, mostly hydrogen, the first element on the periodic table, with one proton.
Under the force of the proto-star’s enormous gravity, hydrogen atoms fuse together to produce helium, with two protons.
This nuclear fusion releases a huge surge of energy, and the star is born.
Hydrogen continues to fuse into helium, releasing more and more energy.
Helium atoms then fuse into carbon atoms, which fuse into silicon atoms, with each subsequent element being heavier.
All this nuclear fusion releases more energy than it takes to fuse the atoms together. And so, the process continues, for millions of years…until the elements fuse into iron.
At that point, it would take more energy to fuse iron into something else than the resulting reaction would produce.
So fusion stops, and the star begins to die.
Soon, the gravity of its iron core becomes so strong that the star collapses on itself, then explodes outward in a supernova, scattering iron across the universe…which eventually forms planets like ours. And our cars. -
Why did the ancient Greeks build their cities in earthquake zones? For several—very good—reasons.
Greece and Turkey lie along massive fault zones. Faults, when they move, create earthquakes. Spring water tends to follow these fault systems, and the Greeks, following the water, did, too.
Fault lines also create cliffs, which provided natural defenses for the cities. And fault zones tend to form surface depressions where soils can accumulate, making them good for agriculture.
So the faults gave Greek cities water, protection, and fertile soil—but it gave them something else, too.
Many of the fresh-water springs were heated along fault zones.
The Greeks built baths and temples at these hot springs, some of which emitted gases that could induce human trances.
At the famous Temple of Apollo at Delphi, traces of ethylene, which produces a state of euphoria, have been found. These fumes were known as the “Breath of Apollo” and may have helped the priestess communicate with the gods.
Other cities and sanctuaries were built along faults that the Greeks believed were entrances to the underworld.
When an earthquake toppled their structures, they usually rebuilt in the same spot…unless the quake also cut off the water supply.
Earthquakes in the time of the ancient Greeks were considered mystical events. And before multistory buildings, the risks of living on fault lines were offset by the many benefits. -
In 1769, Ben Franklin was the first to map the Gulf Stream. It’s Earth’s most famous current, moving more water than the Amazon River.
But the Gulf Stream is just one part of the global ocean conveyor, a system of currents that connects the world’s oceans.
In tropical seas, wind and tides drive warm surface currents, like the Gulf Stream.
Near the poles, cold air, evaporation, and ice formation make the seawater colder and saltier. It sinks to the bottom, and warm tropical water is pulled up to take its place.
In this way, the global ocean conveyor carries tropical heat toward the poles. And carries nutrient- and carbon-rich water from the poles to the tropics, where it feeds phytoplankton, the base of the world’s food web.
The conveyor’s stability over more than 10,000 years has helped regulate climate, weather, and fish populations, contributing to the rise of human civilization.
But since 1850, before the Industrial Age, the Gulf Stream has shown signs of slowing. It’s at its weakest in 1,000 years.
In 2009 and ’10, it moved a third less warm water than usual, causing colder winters in the Eastern U.S. and Europe.
Melting ice in the Arctic has been releasing freshwater onto the ocean surface, disrupting the flow of the cold, salty waters that drive the North Atlantic part of the ocean conveyor.
In this way, paradoxically, a warming climate can bring colder winters in the north. -
Would you let your kids keep a pet shark? You would if you were part of the Bajau tribe, where children learn to swim before they can walk and spear fish at age 8.
The Bajau are sea nomads in Indonesia, the Philippines, and Malaysia, who live on boats and follow fish populations.
Traditionally, they come ashore only to trade their catch and escape storms.
To make their living diving for fish, the Bajau have adapted to do things the rest of us can’t. In fact, they’ve developed some of the same capabilities as seals and whales.
When they dive, their bodies direct blood away from their extremities and toward their brain and organs.
Most importantly, they’ve developed 50 percent larger spleens, which act like an oxygen reserve, storing and then releasing more red blood cells into their systems when they dive.
All Bajau, even those who don’t dive, have an enlarged spleen, indicating it’s genetic.
With these adaptations, most Bajau can spend 5 hours a day underwater. They dive easily to 60 ft and stay there for minutes at a time!
They can go to depths over 200 ft with nothing more than wooden goggles and weight belts to pull them to the bottom. Then surface and do it again.
Western scientists are studying the Bajau to see how they can thrive with less oxygen—a condition called hypoxia, which can cause free divers to lose consciousness and drown.
Perhaps the secrets of the Bajau will save lives elsewhere. -
We know that life evolves, but did you know that minerals do, too?
Remarkably, one of the biggest drivers of mineral evolution… is life.
A mineral is simply an element or elements on the periodic table, arranged in a certain crystal structure. For instance, the hardest mineral, diamond, is formed of the element carbon.
One of the softest, graphite, is also formed of pure carbon, but it’s a different mineral because it has a different crystal structure.
When Earth formed, over 4.5 billion years ago, there were just 12 minerals, including diamond and graphite.
Over the next 2 billion years, plate tectonics began to act on mineral evolution.
Earth’s crust was subducted into the mantle, melted, remixed, and recycled, and the number of mineral species gradually increased to 1,500. And there it stopped…
Until life developed.
Early algae and phytoplankton converted huge volumes of carbon dioxide into oxygen.
This new oxygen-rich environment produced more than 2,500 new oxide and hydroxide mineral species.
Microbes then began to transform minerals chemically, and this added another 500 mineral species.
Multicell organisms evolved and interacted with existing minerals to build their exoskeletons, shells, bones, and teeth, in the process creating hundreds more mineral species.
Because Earth has plate tectonics and life, it now has over 5,000 minerals—10 times more than any other planet in the solar system. -
We talked about the asteroid that, 66 million years ago, ended the age of dinosaurs. But what exactly did it do to the planet?
From the point of impact, a blast wave of heat rushed outward at nearly the speed of light, followed by scorching winds that reached 500 miles an hour.
These were followed by a massive earthquake felt around the world that may have caused landslides across the planet.
Shortly after came tsunami waves up to 1,000 ft high, racing across the Gulf of Mexico and traveling many miles inland, up the Mississippi River, covering Caribbean islands and swamping Atlantic coastlines.
Debris from the impact rained across the region, forming deposits up to 1,000 ft thick. The debris was hot enough to ignite massive wildfires across North America that may have burned for months.
And the long-term effects were even worse!
Ash and dust blocked out sunlight, while billions of tons of vaporized rock formed aerosols that blocked the sun’s heat.
In this cold twilight, the surface temperature of Earth fell as much as 40 degrees Fahrenheit and stayed that way for 15 to 20 years.
Mere decades later, once the aerosols settled out, greenhouse gases from the wildfires helped to warm the atmosphere more than 10 degrees higher than pre-impact.
It’s amazing that anything survived this destruction!
But it actually paved the way for… you and me, which we’ll talk about on another EarthDate. -
On previous EarthDates, we talked about the asteroid that wiped out the dinosaurs—and 75 percent of all species on Earth. But what survived? And how?
In the first years after impact, dust and aerosols blocked the sun’s light and heat, which slowed photosynthesis.
Plants died, along with most things that depended on them, as the food web collapsed.
Most types of plankton in surface ocean waters also died, and rained down through the water column, where bottom-dwelling scavenger species had a field day.
Large organisms with fast metabolisms and higher food needs starved, while some species of less than 50 lbs with slower metabolisms hung tough.
Specialized species suffered worst. Generalists that could more easily adapt fared better.
Early mammals and birds—avian dinosaurs—quickly began to fill the environmental niches left empty by extinct larger species.
Within 300,000 years, a blink of an eye in evolutionary terms, there were productive ecosystems across Earth.
Strangely, one of the places productivity recovered fastest was within the asteroid crater. Scientists are studying why.
It would be another 10 million years before evolution filled all empty environmental niches and the diversity of life equaled what it was before the impact.
The resulting mix looked very different than before and allowed the rise of mammals and birds and, eventually, humans. -
Spider silk is the strongest, most durable, most elastic fiber in the world. It’s 5 to 6 times stronger than steel by weight. A strand that could circle the globe would weigh less than a bar of soap!
Given these remarkable properties, scientists have studied it closely.
Spiders make silk with their spinnerets, tiny organs beneath their abdomens.
Before it’s spun, the silk is a gel of liquid proteins. The spinnerets remove water from the gel and extrude it through an acid bath, aligning the proteins into a solid fiber.
Each spinneret has multiple spigots. And each of those makes a single filament that the spider combines to create different silks: fine or coarse, sticky or not.
Scientists haven’t been able to re-create spider silk chemically, so they’ve enlisted another silk-spinning creature to help: the silkworm.
While spiders are almost impossible to domesticate, the silkworm has thrived in captivity for centuries. Its silk is beautiful but comparatively weak.
So scientists turned the worms into real-life Peter Parkers, giving them genes from the spider.
These genetically modified silkworms spin their cocoons as always, from a single kilometer-long strand—but this time of spider silk.
Other scientists have developed genetically modified bacteria that organize proteins similar to how spider spinnerets work.
With these developments, we may soon have fabric and other materials with the amazing properties of spider silk. -
Previously, we talked about how Earth transfers naturally produced carbon between sky, sea, and soil.
Today, scientists are working to put CO2 from fossil-fuel combustion and agriculture back into the ground rather than into the atmosphere—by mimicking Earth’s natural carbon cycle.
Capturing and compressing CO2 from the exhaust stream of, say, a coal power plant, is challenging and expensive. But when done, the gas becomes a low-density liquid.
Researchers have developed and tested methods to pump it deep underground—into depleted oil fields, coal seams, and rock formations whose small pores are filled with saltwater.
Once there, it dissolves and the saltwater becomes carbonated, less than a soft drink. Studies suggest that carbon can remain trapped in these formations indefinitely, similar to the way hydrocarbons are trapped.
While international tests of these processes have been successful, other more experimental methods are striving to turn CO2 gas into useful solid materials.
New trials have injected CO2 into volcanic basalt, where it formed carbonate minerals.
Others combine carbon and calcium, similar to the way snails and clams draw them from seawater to make their shells.
The challenges with all these methods are expense and scale. Storing enough human-produced carbon to make a difference on the climate, in the time frame needed, will not be easy.
But thanks to government and industry investment in research, we now have enough experience to begin large-scale tests. -
In the mid-twentieth century, NASA scientists launched the first satellites to view Earth.
When they looked at the photos, they saw mysterious stripes of clouds crossing the oceans.
On closer inspection, they realized these cloud trails followed the shipping lanes.
In the mid-nineteenth century, after collisions between ships, nations designated lanes across the seas that ships would follow to avoid accidents.
As traffic grew over the twentieth century, more and more ships plied these maritime highways. But what caused the clouds?
Scientists realized that the exhaust plumes of hundreds or thousands of diesel-fired ships carried streams of aerosols and fine particulates into the low atmosphere, along the shipping lanes.
Water vapor condensed on these to form the trails: the ships were making their own clouds.
Newer satellites discovered something more. They picked up magnetic pulses from lightning patterns across the ocean, and the lightning also followed the shipping lanes.
Scientists now understand that the tiny water droplets in the ships’ cloud trails, finer than in regular clouds, are more conducive to lightning formation.
The ships actually make their own lightning storms, and the weather in their wake is more severe than over open ocean.
So if you’re having one of those days when it feels like a storm cloud is following you around—if you’re the captain of a cargo ship, it just may be. -
On their maps of the West, Lewis and Clark called it “the Great Unknown.”
For a one-armed geologist named John Wesley Powell, that was too much intrigue to ignore.
So in 1869, he led a team in four wooden boats on an expedition down the Green and Colorado Rivers, destined for what the Spanish called El Gran Cañon.
Within 2 weeks, a rocky rapid had destroyed one of their boats.
Within 2 months, most of their supplies were lost. Fortunately, the lightened boats rode higher in the dangerous waters.
Once in the canyon, the rapids echoed in a deafening roar. At times, the men climbed the walls to sleep in the relative safety of rock ledges.
At one point, the party was unable to portage their boats around a seemingly impossible stretch of rapids.
Three men refused to go further and tried to climb out of the canyon, while Powell and the others took two boats and pressed on.
Powell’s group made it through alive and signaled for the others to take the last boat—but the three men were never heard from again.
After 99 days, Powell and his remaining team reached their destination, but he had lost many of his records from the trip.
Unsatisfied, he returned 2 years later to do it again!
These remarkable journeys, as bold as Lewis and Clark’s Discovery Expedition, launched a movement to declare the Grand Canyon a national park. -
The Roman Empire had official historians—but can we trust their accounts, or were they burnishing history to please the emperors? A closer look at Roman silver has helped find the answer.
And surprisingly, this closer look came in Greenland. The ice there has recorded 130,000 years of history, as the atmospheric particles of each year are deposited in a layer of ice, one atop the other.
By drilling ice cores, then analyzing these layers with microscopes and spectrometers, we can read them like tree rings to build a detailed picture of the atmosphere over time.
This has helped today’s scientists study ancient climate, volcanic eruptions, and the success or failure of agriculture as told by pollen grains. It’s also revealed a lot about Rome.
The coin of the realm was the denarius, made of silver smelted from galena, a lead ore.
When the Roman economy was booming, smelters across the Empire pumped out silver, and spewed lead fumes into the atmosphere—which wafted across Europe to Greenland, where they settled on the ice and were preserved.
When the economy slumped, the smelters went quiet, and lead-laden emissions declined.
Researchers have now analyzed the lead levels, and they closely correspond to Rome’s official history—falling during wars and in times of plague, rising after wars and in times of peace.
Rome’s imperial storytellers largely agree with the ice cores, an admirable truth in journalism that spanned 600 years. -
One hundred sixty years ago, scientists invented the spectroscope, which breaks light into its spectrum of colors.
They soon discovered that some elements, when heated, produce a signature light color. Hydrogen, for instance, makes orange.
When they pointed the spectroscope at the sun, they saw lots of orange—and some yellow, which didn’t match any element on Earth.
They named this alien element helium, after the Greek sun god Helios.
For decades, many doubted its existence. Until a scientist aimed the spectroscope at lava and saw the yellow again. Helium had been found on Earth.
Further study revealed that helium was being produced by the decay of uranium and trapped underground in reservoirs. It also revealed that it’s a very special element.
Helium is so light that Earth’s gravity can’t hold it. When released at the surface, it rises through the atmosphere into space.
It’s also inert: helium won’t bond with other elements, meaning it’s nontoxic and nonflammable. That makes it useful to create sterile, nonoxidizing environments for medical procedures, clean rooms, and welding.
Helium also enters its liquid state colder than any other element. Liquid helium is therefore used to cool superconductor magnets, and in MRI machines and nuclear colliders.
So next time you see helium balloons at a party, or inhale it to sing happy birthday in a chipmunk voice, remember that helium itself is an element worth celebrating. -
Scientists have been watching 1,000 species of mountain animals and plants around the world to see how they react to a warming climate.
They’ve found that as annual temperatures climb, many species have climbed, too. On average, for every one-degree-Celsius increase, mountain-dwelling species shifted 100 meters upslope.
Because the mountains narrow as they go up, this means a shrinking habitat for those species, and often a dramatic drop in population.
For instance, butterflies in the French Pyrenees and gophers in Nevada’s Ruby Mountains have lost 70 to 80 percent of their range, as suitable habitat shifted up the slope.
Birds on one mountain in the Peruvian Andes moved 250 meters up over the past 30 years in response to a change of just one degree.
Some of the migrating species are soil microbes, which, as they move upslope, may allow tree species to move up with them. In these cases, the treeline could rise, supporting forest species on their upward climbs.
But as the climate continues to warm, earthbound species like trees, crawling insects, and mammals will eventually run out of mountain. If they can’t adapt to the warmer temperatures, they may die out.
Birds and flying insects would be able to fly to higher ridges and mountaintops—as long as there are higher ones in the region.
Regardless of cause, these are effects we can measure and observe today: plants and animals the world over are migrating to adjust to a warming climate. - Mostra di più
