EarthDate

The oldest individual trees are conifers—but they’re not the famous sequoias. Some of those exceed 3,000 years. But bristlecone pines are centuries, even millennia, older.

They’ve adapted to small, high and dry ranges in eastern California, Nevada and Utah, just below the tree line.

The oldest trees live in the harshest conditions, where few other plants can grow, so they’re less likely to be exposed to fire, insects or disease. And the oldest of them all was a tree named Methuselah.

Bristlecone pines have unusual...

A thousand years before the Inca, in the deserts of Peru where rainfall is almost nonexistent, lived a civilization so advanced they’d figured out how to use wind to pump water.

The Nazca people were fantastic artists, famous among anthropologists and ancient art collectors for their textiles and ceramics. But they were also brilliant engineers.

Over generations, they constructed a sophisticated water system.

They trenched and tunneled into the gravelly water table of the Andean foothills, then built underground aqueducts, lined with smooth river stone, to mo...

Besides a few very committed scientists, there’s only one organism that can live on the continent of Antarctica year-round. It’s not a penguin or a seal; they live mostly at sea.

No, it’s the tiny Antarctic midge, just a quarter inch long and extremely adapted to the extreme environment.

Midges are small insects that usually fly and bite hosts to feed on blood. The Antarctic midge does neither.

Like many insects in very windy places, it has lost its wings to keep from being blown...

On November 1, across Latin America but especially in Mexico, the cemeteries come alive—with a celebration.

It’s Dia de los Muertos, the Day of the Dead. Legend has it the gates of heaven open for a day to allow the souls of the dead to reunite with loved ones.

It’s considered disrespectful to mourn the dead, so families bring food and drink, clean and decorate gravestones, sing, and dance, fly brightly colored kites, and tell stories about and for the deceased.

Dia de los Muertos is a m...

Mesopotamia, in the Middle East, is known as the birthplace of civilization. Two of its early civilizations mysteriously collapsed, which baffled researchers until they found the reason—in stalagmites.

Around 10,000 years ago, hunter-gatherers there developed agriculture and domesticated animals. Abundant food and animal labor allowed them time to invent: the wheel, glassmaking, and eventually writing.

This set the stage for the world’s first empires: the Akkadians then the Neo-Assyrians controlled all of Mesopotamia, though a thousand years apart. And both suddenly vanished.

Recently, some geologists went look...

As we know, birds descended from dinosaurs. And with 18,000 species of bird now living, there may be more “dinosaur” species today than ever before. The birds that share the most DNA with their dinosaur ancestors are, surprisingly, the chicken and the turkey.

The turkey, like the tyrannosaur, has a wishbone and a similar hip structure. And it has meaty drumsticks and thighs like a Velociraptor. Yum!

The turkey probably evolved from prehistoric birds in South America and migrated northward.

During the last Ice Age, the California turkey was...

We’ve talked before about how lightning breaks nitrogen molecules into nitric oxide—which falls to Earth in rainwater and nourishes plants.

But we now know that lightning storms have another essential function.

After forming nitric oxide, a secondary reaction makes oxidants, which clean the atmosphere.

Oxidants are essentially water molecules that lost a hydrogen atom. To replace it, they react with other compounds, including methane and CO2.

They oxidize these into other forms that also fall to Earth in rain, thereby reducing gree...

Whakaari/White Island is New Zealand’s largest active volcano. Its crater forms a huge natural amphitheater that opens to a bay.

In December 2019, a large group of tourists arrived for a day trip. They donned gas masks to watch fumaroles spew clouds of yellow steam.

Then, disaster struck. The volcano erupted suddenly, belching vapor and ash two miles into the sky. The cloud collapsed into the amphitheater, which funneled it directly at the tourists.

Half were killed and the other half suffered severe burns and lung da...

Here are two trivia questions for you: What’s the strongest metal on Earth? And why is it called “wolf cream”?

It was discovered in the 1400’s when miners found a hairy black mineral with tin ore. When they smelted the two together, the surface of the melted ore foamed and a heavy slag consumed much of the tin.

They named the mineral “wolf” for its furry appearance and appetite for tin and “rahm” or cream for the foam. Wolfram. In Europe, it’s still called that.

But elsewhere, it...

We’ve talked a lot about fossils on EarthDate, but we’ve never talked about how they form.

Normally, when a plant or animal dies, it decays or is consumed. But occasionally its remains are preserved as a fossil.

This usually happens when the organism is buried quickly in sediment. The sediment layer protects it from the elements, scavengers, even oxygen. Often soft parts decompose, leaving bones, teeth, shells, or exoskeletons.

As the sediment gradually hardens into rock, mineralized water is absorbed into the pores of the rema...

Until Marie Tharp came along, no one knew what the seafloor really looked like.

It was long thought to be a featureless plain of mud.

Then sonar, invented in World War II, began to give us a glimpse. But it could only “read” the bottom of the ocean right below the ship’s path.

Marie Tharp earned master’s degrees in geology and mathematics in the 1940’s and joined the navy to study the seafloor—but women were not allowed on research ships.

Instead, she...

Bloodletting with leeches seems a very primitive practice. So, it may surprise you to know it’s still very much in use today.

There are 700 species of leech. Most dwell in water and drink blood from fish, turtles, ducks, frogs and other creatures. Scientists can even track which animals are living in swamps and rainforests by capturing leeches and DNA testing the blood in their stomachs.

Leeches were first used in medicine at least 2,500 years ago. They became so popular in nineteenth-century Europe that overharvesting made them threatened.

...

DNA is like a fingerprint. Each species’ DNA signature is distinctive. And it can be found on the scene long after the individual has gone.

For some time, scientists have gathered the DNA that organisms leave behind—in saliva, urine, feces, fur, and flakes of dry skin—to detect their presence and study them.

They’ve found this so-called environmental DNA, or eDNA, in water, soil, even snow.

But scientists wondered if they could gather it more easily and broadly by capturing it out of thin air.

When the explorer Ferdinand Magellan finally made it ‘round the treacherous horn of South America in 1521, the ocean beyond seemed especially calm—so he named it the peaceful sea: Mare pacificum, the Pacific Ocean.

Little did he know the Pacific is anything but. It’s surrounded by more than 1,000 volcanoes that make up what’s now called the Pacific Ring of Fire—a geologically active strip 25,000 miles long, in places 300 miles wide, that borders the Pacific on three sides.

It would be more than 400 years later, in 1960, that scientists could understand what was g...

Think about this: a tree could be 100, 200, more than 300 feet tall, yet can lift water from deep underground all the way to the leaves of its highest branches. Each day it could move hundreds of gallons, several tons of water this way.

This gravity-defying feat is made possible not so much by the tree but by the properties of water itself.

Trees perform photosynthesis in their leaves, which requires water. The hydrogen in water goes to form carbohydrates—sugar, the food for the tree. The oxygen is exhaled through pores in th...

There’s a common houseplant that in the wild can do what no other plant can.

It’s the staghorn fern.

It’s an epiphyte, meaning it doesn’t need soil but instead grows on a larger host plant and draws its nutrients from water and air.

But that’s not what makes it unique.

Normally a staghorn has two types of fronds. One is green, antler shaped and produces spores. The other is brown, strap-like and sterile, and attaches the fern to the host.<...

You’ve probably heard that black cars get hotter than white cars.

Scientists set out to measure the difference. They parked two otherwise identical cars in a sunny parking lot, and, sure enough, the white car’s interior stayed 17 degrees Fahrenheit cooler.

Urban planners hope to use the same principle to cool cites, where miles of black asphalt and dark colored roofs absorb the sun’s heat, amplifying daytime temperatures, then radiate the heat through the night.

The famous white villages of Spain have addressed this issue for ce...

There’s a special place in South Africa called Border Cave where our ancestors already in modern human form lived continuously for nearly a quarter million years.

Excavating in the cave is like reading backward in a history book, finding evidence of each earlier generation in each deeper layer.

The cave has yielded 69,000 artifacts, a treasure trove of clues to human prehistory, and digs continue to this day, with surprising new findings.

For instance, scientists recently discovered the remains of sleeping beds from 200,000 years ago. These consist of...

There’s one source that provides almost a third of the water for all US agriculture. It’s called the Ogallala aquifer, stretching under the Great Plains from South Dakota to northern Texas.

Once considered inexhaustible, we now understand its limits.

For the first settlers in the Great Plains, water was scarce and farming was difficult…

Until the 1850s, when they began to use windmills to pump up groundwater from the aquifer. Suddenly they had all they needed and an agricultural boom was on.

Farm...

Tiny mosses were the first land plants to evolve on Earth. But the first real plants, the big leafy kind, came on the scene 400 million years ago—200 million years before hardwood trees and flowering plants.

I’m talking about ferns.

They flourished, then and now, through a unique two-stage life cycle.

Mature ferns produce spores that drop to the ground. There they grow into gametophytes, which don’t look anything like the mature example. In some species, they grow underground.

The gametophytes produce eggs a...

It may surprise you to know that one of the most important minerals in history has been … potash.

Many centuries ago, humans discovered that if you took a pot, put in wood ash, boiled it then strained out the residue, you’d get potash—which had two very special qualities.

First, when mixed into soil it made an excellent fertilizer for crops. Second, when mixed with sulfur and charcoal it made gunpowder.

Potash was so valuable that the very first U.S. patent, signed by George Washington himsel...

Some very old oyster shells found in a cave have answered the eternal question, “who was the first person to eat that”?! Looks like it was a hungry South African, 164,000 years ago.

Today, we consume around 8 billion oysters a year. But they’re good for so much more than eating.

Oysters cement themselves together to form reefs that control coastal erosion and reduce wave energy.

These reefs increase the surface area 50 times compared to a flat ocean bottom, providing habitat for many other species.

Oyst...

Only one ten thousandth of Earth’s total water supply is fresh water on the surface, to keep billions of humans and other animals alive. Good reason to conserve it—which also saves energy and money.

Water is heavy, so it takes energy to move it. The farther it’s pumped in pipelines or carried in trucks, the more it costs the user. Water purification systems also require energy, adding to the price.

Sending more water down the drain increases the volume that must be processed to use again, increasing energy and co...

The word monsoon may conjure in your mind torrential rains. But monsoon actually comes from the Arabic mawsim—meaning not rain but season.

In the tropics, there are only two seasons, known as dry and wet monsoons. They’re brought about by equatorial winds that blow in each spring and fall—predictably enough that sailors have depended on them for centuries.

During wet monsoons, the winds bring rain in tropical places around the world, like India and Southeast Asia. But also in the subtropics—like the American Southwest, Central America, northern South Am...

The meteorologists who invented weather radar never expected to be studying bugs. But today they do.

There are 159 weather radar stations in the US. They look like giant golf balls on towers. There’s a rotating dish within the white sphere that sends radio pulses into the sky. When they meet something, some of the radio waves bounce back.

The radar reads the time and strength of the returned waves to determine the distance and concentration of the object they encountered. Like a cloud.  

As weather radar has...

A recent discovery has reshaped our understanding of human history in North America.

A few EarthDates ago, we talked about a tribe of Siberians who were stranded in the Bering Strait for centuries before migrating into North America to become its first citizens 16,000 years ago.

Turns out, they weren’t first. Because in White Sands National Park, scientists have found something remarkable.

Modern visitors to this dry southeastern corner of New Mexico, who happened to come during one of its rare rainy spells, sometimes reported seeing “ghost foot...

At the bottom of one of Africa’s deepest lakes lies a secret that could put two million nearby residents in danger.

Lake Kivu sits along the East African Rift Valley, where the tectonic plates that bisect Africa pull apart.

Volcanoes leak natural carbon dioxide into the bottom of the lake, where the water pressure is high enough to dissolve and concentrate the gas in water.

If the water temperature changes, or the water column is overturned, the CO2 can suddenly turn to gas again and shoot to...

The Andean Condor is a giant vulture that lives along South America’s west coast. It’s one of the heaviest flying birds in the world, weighing more than 30 pounds. Yet it can stay aloft for hours at a time.

How do condors do it? Efficiency!

The condor launches itself from a high peak or cliff, spreads its massive wings—the largest in surface area of any living bird—and soars.

It will then ride thermals, currents of hot air rising from the ground, scanning the land below fo...

Gold is malleable, portable, nontoxic, beautiful and rare. Those qualities have made it an excellent currency over the centuries.

But there’s another metal with all those properties and more—and it’s much more valuable.

It’s called rhodium, part of the platinum group of metals. The name comes from the Greek rhodon, meaning rose, for the rosy color of rhodium compounds.

It’s abundant in other parts of the universe but vanishingly rare in Earth’s crust—just one part in 200 million. We mine 100 times more gold each...

In 1836, Charles Darwin and his colleague Joseph Hooker visited Ascension Island, really just a barren pile of volcanic basalt topped by an old cinder cone, ironically named Green Mountain.

There were very few plants, but some soldiers had successfully grown a vegetable garden in the volcanic soil. This gave Hooker a crazy idea. He contacted his father, the director of the botanical garden in London, and persuaded him to send plants.

Hooker and Darwin believed that if they could establish a thriving plant colony on the island, it would trap water...

Fireflies are sometimes called lighting bugs or glowworms. But they’re not flies, bugs or worms—they’re beetles, with a marvelous capability.

They move oxygen through a tube in their abdomen to combine it with a special pigment called luciferin to produce bioluminescence, the familiar glow that gives fireflies their name.

There are 2,000 species of firefly around the world and 170 in the US. Different species produce different colored light, from bright red to fluorescent green.

And they flash their light differently too.

Males...

Microscopes, telescopes and lenses. Smartphones, laptops and televisions. Mirrors, windshields and cathedral windows.

None would be possible without glass.

It’s made of silicon dioxide, or quartz, that’s melted and then cooled so fast that crystals can’t form, which gives glass its most important quality today: transparency.

But glass was first valued for the way it breaks. Early humans found naturally occurring glass— from volcanoes or when a meteor superheated desert sand—and used its broken shards to cut things or make weapons.

Not t...

Scientists have a new way to measure rain, or rather, rain intensity.

They looked at data from 185 weather stations across the globe, from 1999 to 2014, to determine how much rain fell in how many days.

They found that, on average, one twelfth of an area’s rain falls in its single wettest day, one eighth in its wettest 2 days, and half in just 12 days.

They decided to standardize this metric—the number of days it takes for half the rain to fall—as a way to gauge rain intens...

We’re all familiar with those violent shaking events we call earthquakes. But it may surprise you to know that Earth more often moves without quaking in what’s called a slow or silent slip. It sure surprised scientists: they discovered this just 20 years ago.

Earth’s tectonic plates began to move over a billion years ago. Their constant motion has formed, pulled apart, and slowly destroyed continents for millennia.

Each tectonic plate rotates around an axis, while its edges collide with, slide over, or subduct under other plates.

W...

Landslides happen when a slope becomes unstable—because of denuding, from a fire or deforestation; over-steepening, from erosion or mining; overloading, from a reservoir or heavy snowpack; or oversaturation, with rain or melt water.

So many things can cause a landslide that they happen in every U.S. state and nearly every country.

When the slope gives way, soil can speed downhill at 50 to 100 miles an hour, carrying trees, boulders, cars, even houses.

Earthquakes trigger just five percent of landslides. Twenty percent are caused by human activities, wh...

The South Pole is the most inhospitable place on Earth—yet, each year, around 50 brave scientists and staff endure the winter there. Outside temperatures approach minus 120 degrees Fahrenheit in constant darkness.

And they better hope nothing goes wrong. Because no one can come to help them.

The South Pole is 800 miles from the nearest human contact. That’s farther than the International Space Station, which orbits less than 400 miles above Earth.

From research bases on the Antarctic coast, it takes planes 5 to 8 hours to fly to the Sout...

Herbivores eat plants, and carnivores eat animals that eat plants, to get their energy.

Plants and many bacteria create their own energy through photosynthesis, which depends on chlorophyll…which requires nitrogen.

As we’ve described in other episodes, most nitrogen on Earth is in the form of N2, the inert nitrogen gas that won’t bond with other compounds, making it useless to plants.

So, most plants rely on bacteria that cling to their roots and split the nitrogen in the soil for them. But when they can’t...

There’s an Irish saying, “There’s a pot of gold at the end of every rainbow.”

But it used to say, “you’re as likely to find a pot of gold as the end of the rainbow.”

That’s because if you go looking for its end, the rainbow vanishes.

Rainbows occur when water droplets—from rain, mist, waterfalls, even sea spray—hang in the air.

When sunlight enters the droplet, some will reflect off the back side and pass again out the front.

There are no snakes in Ireland. Because, according to legend, St. Patrick expelled them. True, or folk tale?

St. Patrick, ironically, wasn’t Irish. Or, named Patrick. He was born Maewyn Succat in 390 AD in Britain, kidnapped by pirates at 16, and held in slavery in Ireland for 6 years.

He escaped and joined a monastery in England. Then decided to return to Ireland as a missionary, where he converted Druids and built the first church.

He died in 460 AD in Downpatrick, hence the name. A few centuries later, he...

In the 1800s, scientists found a 400-million-year-old fossil fish they thought could be the missing link between aquatic and land-dwelling creatures. They would have loved to study it, but it had gone extinct with the dinosaurs.

Or so they thought. Until 1938, when a museum curator saw a fisherman haul one out of his net in South Africa. She wrote a hasty telegram to her museum. They wrote back: “Get that fish!”

She had found the coelacanth, not extinct after all, but hiding for millions of years in the Indian Ocean.

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