Episodes

Sponges may look like plants, but they’re animals—some of the longest-lived on Earth, with a few living more than 10,000 years. They’re also the least evolutionarily advanced creatures on the planet. But new accidental findings may show we’ve underestimated them. Sponges evolved more than 500 million years ago, flourished through Earth’s great extinction events, and have endured ever since. Today there are 6,000 known species and new ones being identified regularly. Sponges were thought to b...

Penguins have been around a long, long time. They first evolved more than 60 million years ago when the asteroid that wiped out the dinosaurs opened a niche for them. Fossils suggest they were already flightless, but they took to the sea where they became perfectly adapted: Their feathers are coated in oil. Their body is insulated in fat. Their wings are shaped like flippers, making some penguins twice as fast as the fastest human swimmer. Their bowling-pin shape doesn’t look athletic, but i...

On Super Bowl Sunday, Americans eat 26 million avocados in our guacamole. Annually, we average 8 pounds of avocados per person. A third of the world’s supply comes from Mexico, which is where the avocado developed. It began as a small black fruit called the criollo from the same family of trees that produce bay leaves and cinnamon. The fruit was a favorite of giant herbivores, similar to today’s rhinos and elephants. They would ingest the fruit and poop out the seed, propagating the trees. W...

In 1492, Columbus sailed the ocean blue. But… In 1021, the Vikings landed in Newfoundland. That’s right, we’re now certain that Norse explorers reached North America nearly 500 years before the Spaniards. It happened at L’Anse aux Meadows, in easternmost Canada, where explorers in the 1960s discovered the remains of Viking longhouses. But they didn’t know exactly when they arrived or left. We now know they were here exactly in 1021. That’s because a team of scientists has figured out how to...

The 2020 Census counts 331 million people living in the USA. Worldwide there are now almost 8 billion. Which means the United States represents just 4 percent of the total global population. China and India, with nearly 3 billion people combined, make up about a third of total population. Researchers also recently calculated a global biomass census to compute the total weight of all things living on Earth. Biomass is measured in metric tons of carbon because all living things are made of car...

For 500 years, explorers have looked for a passage above North America, from the Atlantic to the Pacific. With a warming Arctic, they’ve finally got it. Which could have profound impacts on geopolitics. In the 1500s, Spain and Portugal controlled the sea routes to their colonies in the Americas. Northern Europeans, looking for their own way to reach Asia, began searching for a Northwest Passage through frigid Arctic seas. For centuries, voyagers endured winters frozen in ice, where entire cre...

The Australian bushfires of 2019 produced so much smoke, it entered the stratosphere, 19 miles above Earth! On an earlier episode, we talked about how fires make their own weather. As a column of hot air rises from the flames, it carries smoke into the atmosphere where it forms clouds. Water vapor may condense around smoke particles and rain down to quench the fire. Or lightning may form in the clouds, which could cause more fire risk. The Australian fires produced 100 million tons of smoke. ...

Before antibiotics, millions died each year of diseases we can easily treat today. If we’re not careful, we may be headed back to those deadly days. In 1928, Alexander Fleming discovered that a fungus, Penicillin rubrum, could kill bacteria. But his fellow doctors wouldn’t listen. It wasn’t until 1943, when he cured a patient dying of meningitis in just one week, that they finally paid attention. Fleming won the Nobel Prize but cautioned that bacteria could grow resistant to penicillin—if the...

When conditions turn extreme and food and water get scarce, many creatures shut down their metabolism and go into suspended animation. This is much different than sleep. Body temperature drops to near the ambient temperature. Bodily functions slow, with some stopping altogether. This dormancy comes in several varieties: Some species go into daily torpor in the heat of the day. Hummingbirds, for instance, will find a shady place to shut down, and drop their heart rate to just 5% of normal. De...

Wooly mammoths lived in Siberia and North America from about 5 million to as recently as 4,000 years ago. They stood the same height as African elephants, up to 11 feet at the shoulder, but with long shaggy coats and much longer tusks. Within one of those tusks, scientists found a remarkable story. Mammoth tusks were just specially developed teeth, which grew new layers every year, from the inside. Recently, scientists measured strontium in each layer of a tusk from one mammoth found in Alas...

In 1858, the first transatlantic telegraph cable was laid. It worked slowly—taking 2 minutes to transmit each character of a message. But that was a lot faster than the old way: ships, which took at least 10 days to make the journey. That first cable failed after 3 weeks, but it showed it could be done. By 1900, there were a dozen cables connecting North America and Europe. This ground to a halt in 1929 when all 12 cables broke in one day. No one could figure out how it had happened. But spe...

Over the past 2.5 million years, glaciers have descended from the arctic to the Central United States 17 times—before receding again in warmer periods, like we’re in today. This repeated glacial coverage has flattened the land, producing the rolling prairies of the American Midwest. But there’s one place along the Wisconsin–Iowa border that the glaciers missed. As they move, glaciers grind beneath them, and push in front of them, rock and earth. When they retreat, they leave this material behi...

You may have seen meteor showers and wondered what they are. Well, most are actually the icy tails of comets. As comets travel, they shed particles of dust and ice, then pull them behind in their wake to form a long tail. Each year, Earth’s orbital path passes through the tails of several comets that also orbit within our solar system. When that happens, the particles burn up in our atmosphere. We see them as shooting stars. There’s a particularly bright meteor shower that appears in the sky ...

Here’s a trivia question for you: How many countries today measure temperature in Fahrenheit? We’ll get to the answer through a story. By the 1600s, scientists had invented early thermometers. Using air, then alcohol, then mercury—all things that expand with rising temperature—they could tell you … if it was hotter or colder. But they couldn’t tell you by how much, because no one had standardized a way to measure it. Around 1700, German scientist Daniel Fahrenheit came up with a scale. He fo...

In March 2021, a huge container ship was blown sideways by a sandstorm and jammed diagonally in a narrow stretch of the Suez Canal, blocking it entirely. Because 12% of all global trade moves through the canal, experts calculated its closure was costing the global economy $400 million per hour! The Suez Canal is really just an extension of the Red Sea, a narrow, 1,200-mile-long strip of water that began opening 20 million years ago between North Africa and Arabia. It almost connected the Indi...

Many birds fly long distances during their annual migrations. But there’s one species that tops them all. Some of the farthest flyers are cuckoos, who travel 7,500 miles over 2 months, from Africa to Mongolia, stopping along the way for food and water. This includes one nonstop stretch over the Indian Ocean for 1,600 miles! That sounds impressive, but it’s a walk in the park for the bar-tailed godwit. Godwits are wading birds in the sandpiper family. They spend the mild northern summer along...

It would be hard to imagine a world without paper. The Egyptians invented it three thousand years ago, using rushes that grew along the Nile River. A thousand years later, the Chinese ground up mulberry bark and cotton to make paper for the emperor. In another thousand years, the Moors used linen and hemp. They brought paper to Spain, where it spread to the rest of Europe. It wasn’t until Gutenberg invented the printing press in 1450 that demand rose. But paper was still made one sheet at a ...

The Amazon rain forest. Scientists believe it holds thousands of species of plants, animals and insects we have yet to identify. And at least 50 tribes who have still not had contact with the outside world. But before it could become the marvel it is today, the rain forest had to burn to the ground. That big burn was caused by the same asteroid that wiped out the dinosaurs. Scientists have studied Amazonian fossil plants from a few million years before and after the asteroid to reconstruct th...

It may surprise you to know there are 1,400 species of bats—they make up 20% of all mammal species. They have wingspans ranging from 6 in to 5 ft and occupy dozens of environmental niches. Some are specialized to eat fish. Tiny vampire bats drink blood (usually from sleeping livestock, without harming them). But the most important bats, to humans anyway, are those that eat insects, providing up to $50 billion worth of free pest control for our agriculture every year. They also eat mosquitoes...

In 1891, Manya Skłodowska moved from Warsaw to Paris to study at the Sorbonne. In just three years, she earned two degrees, in physics and mathematics—then took a job with a promising young scientist. They fell in love and were married. She changed her Polish first name to the French version: Marie. And took his last name: Curie. Marie and Pierre Curie became the first to understand and measure radioactivity, then the first to identify the element radium. When he was killed in an accident, s...

If, like me, you think dogs are amazing, you’ll be even more amazed to learn they experience life in four dimensions—through their noses. Dogs have an olfactory bulb 40 times larger than ours, with hundreds of millions more receptors. They use that super-sniffer to build a three-dimensional smell map of their surroundings. Sort of like an interactive 3D computer model. To that, they add a fourth dimension: time. They can smell how a scent has fallen in concentration, or oxidized and changed i...

This story is bananas. But it begins with potatoes. In the mid-1800s, Ireland depended largely on potatoes. The crop was all one species, called the Irish Lumper, grown easily by propagating new plants from old potatoes. It was monoculture in its strictest form: the new plants were genetically identical to the old ones … Which allowed a potato fungus to sweep across the country, devastating Ireland’s potato crop for years afterward. A million Irish died of starvation. Two million left the co...

Phosphorus is one of the five elements essential for life. It’s represented on the periodic table by the letter P. Phosphorus is key to building bones and teeth and as the building block for the fuel that powers our growth and movement. You might remember adenosine triphosphate, or ATP, from high school biology class. Each day the human body makes, uses and recycles its entire weight in ATP to drive our cellular function. Phosphorus is not very common on the surface of Earth, where it’s mostl...

Monkeys make tools. Birds build houses. And ants grow agriculture. Bees live in complex societies, and many creatures use basic language to communicate. It could be argued that the biggest differentiator of humans from other animals is that we have harnessed energy—first and still foremost in the form of fire. Fire kept us warm, allowing early humans and our ancestors to spread into harsher climates. It helped us hunt, then gave us the ability to cook. We gathered around the fire at night, wh...