Episodes

You may remember from a prior episode that some sponges can creep, very slowly, across the ocean floor. But most are stationary, or sessile, which make them seem less interesting. However, we continue to learn just how fascinating, and valuable, sponges are. There are 8,550 species, in all colors, shapes and sizes, in all depths of salt- and fresh water. They survive by filtering water through their tissues to consume bacteria. And this is key to their environmental benefits. They clean the w...

What’s the rarest gemstone on Earth? Diamond? Ruby? Sapphire? Nope, none of these. It’s kyawthuite. The miners who discovered it thought nothing of it. This was in Myanmar, which produces a variety of gemstones: the Burmese ruby, sapphires, spinels, peridots and many others. They’re recovered in several ways. These miners were sifting through river gravel when they found a rough, rust-colored crystal they thought was topaz or amber. Nothing extraordinary, so they threw it in the basket to go...

True to its name, the Venus Flytrap looks like it came from another planet, and it eats bugs. It may seem alien, but carnivorous plants are surprisingly common. There are 750 species, living on every continent but Antarctica. They exist wherever the soil can’t provide all the nutrients that plants need. So they look to other sources—often insects. The Venus Flytrap is the most well-known. Its “jaws” stand open until an unsuspecting fly touches hairs within for several seconds. That triggers a...

Pause for a moment to ponder what a mummy smells like. Stinky? Musty? Dusty? What if I told you ‘woody, spicy and slightly sweet.’ Apparently, that’s what mummy archeologists and scent-expert ‘super-sniffers’ find. The discovery of an Egyptian undertaker’s 3,500-year-old workshop helped researchers understand why. When pharaohs or Egyptian nobles died, they could afford elaborate embalming rituals to prepare for a transition to the afterlife. First the body was washed. Then all organs but th...

Animals evolved their colors to be sexy. But mostly, to be dangerous. Amphibians, reptiles, fish, insects, birds and even mammals sometimes use bright colors to attract mates. Think of the iridescent plumage of peacocks. Or the bright greens, yellows and oranges of a male iguana. But animals are about five times as likely to use bold color—especially red, yellow, black and white—to warn predators that they’re poisonous, foul-smelling or bad tasting. Think of the red hourglass on the black wi...

Rabies is almost 100% fatal. It can affect any warm-blooded creature and is transferred by any bodily fluid – though most commonly by a bite that passes saliva from the infected animal to the blood of another. It takes days or even months for the virus to incubate. But once active, it attacks the nervous system causing paralysis, coma and eventually death. Rabies kills 60,000 people annually worldwide, mostly in Africa and Asia. Before the 19th century, it was far more deadly, because there wa...

Cow manure. Garlic breath. Asparagus pee. What do they have in common? They all stink. And that stink comes from sulfur. Hydrogen sulfide is a very pungent gas that forms when plant matter decomposes, and gives its telltale fragrance to sewage, rotting garbage, and swamps. Sulfur dioxide – the smell of burned matches – is a gas produced when fossil fuels burn, metals are smelted, volcanoes erupt or hot springs bubble up. Organosulfur compounds -- there are millions in nature -- create some o...

As you listen to these words, you’re using energy. The radio in your car is powered by gasoline. Your EV, phone or computer runs on electricity. We rarely stop to think about the massive amounts of energy we use, 24-7-365. And we rarely think about where it comes from. But I can tell you in one word. Because all energy comes from one place: Earth. Oil, gas and coal are fossil fuels, made of ancient plants, algae and plankton, that were covered in sediment, compressed, heated and turned into hy...

Scientists studying Ponderosa pines in a Colorado forest were interrupted by a wildfire – which led them to a surprising discovery. The researchers were investigating the trees’ photosynthesis, during which they take in CO2 through pores in their needles, called stoma. When heavy smoke from the wildfire filled the forest, the scientists had their equipment in place and operating, and witnessed something unexpected: the trees held their breath. They closed their stoma, apparently to stop the sm...

Imagine taking a photo of a speeding car. A fast shutter freezes the car in position but gives no idea of its speed. A slow shutter produces a blurred streak, suggesting speed but not much about position. This analogy applies to electrons. In the 1920s, German physicist Werner Heisenberg was studying them. The closer he came to measuring their positions, the less he could measure their speed. And vice versa. He realized that speed and position are simply uncertain on the atomic scale. He call...

Water bears are so hardy that researchers are studying them to try to advance human medicine. Scientifically they’re called tardigrades. There are over a thousand species living in wet environments, from the deep sea to moss beds in the Himalayas. They may look like bears, but there’s no relation. To begin, they’re microscopic, usually less than a millimeter in length. They have a digestive tract, but no bones, lungs or circulatory system. Their bodies keep their shape by holding fluid within...

The dark side of the moon isn’t really dark. It has a lunar day just like the near side. The far side just seems dark to us, because it faces away from Earth and we never see it. US space missions never landed there, but China was determined to explore it. So, they began a multi-decade, unmanned lunar program, named after the Chinese moon goddess, Chang’e. In 2007 and 2010, Chang’e 1 and 2 spacecrafts orbited and mapped the moon, to determine a landing spot on the near side for Chang’e 3, whic...

Earth may once have had rings, like Saturn – and all the more distant planets of our solar system. Saturn’s are just the most visible, and therefore the most famous. Rings are made of debris – from asteroids, moons, or from the formation of the planets themselves. Scientists think the rings around Saturn are the remains of one of its moons that was torn apart by the giant planet’s gravity. They think the rings around Jupiter are likely dust from micrometeor impacts with its moons. New findin...

In the 1970s, Roger Payne had a multi-platinum record, a surprise hit for two big reasons: Payne was a marine biologist, not a musician. And the singers on the album… were whales. Payne’s “Songs of the Humpback Whale” revealed that other creatures may have complex language. It raised interest in whale intelligence, and led to the passage of laws protecting them. It also encouraged scientists from many different fields to try to figure out what the whales are saying. Project CETI has been stud...

A million Americans listen to this show each week. Some at Earthdate.org. But the huge majority on the radio. That’s because, in our increasingly online world, radio is still the leading way people consume media. It began when an engineer named Reginald Fessenden improved on early transmitters to create a continuous stream of radio waves. In 1906, he made the first broadcast, of himself playing the violin and singing – a one-man talent show … that almost no one had a receiver to hear. That q...

Amber is a “gem” that’s often a window into the ancient past. For thousands of years it’s been valued for its beauty, collected by humans and formed into jewelry and other treasures. But amber is actually not a gemstone, or a mineral at all. It’s fossilized tree resin. Trees secrete resin in reaction to damage. The resin hardens like a scab to seal the injury and protect the tree from disease. But while it’s hardening, it’s extremely sticky and can trap pieces of plants, even small creatures...

Sixty years ago in central Turkey, a homeowner made a remarkable discovery. When remodeling his basement, he knocked down a wall and found a tunnel. He followed the tunnel to find one of the largest underground cities in the world, abandoned long ago. When scientists explored it, they discovered it went down 18 levels, 280 feet into the ground, and was once home to some 20,000 underground dwellers. This was in the region known as Cappadocia, where ancient volcanoes formed soft, porous rock ca...

The most extreme, most inhospitable lands on Earth are the McMurdo Dry Valleys, near the coast of Antarctica, just inland from the McMurdo science base. We normally think of Antarctica as covered in ice. But the dry valleys are surrounded by mountains, which block precipitation. What little water does accumulate is blown away by the constant winds. And yet, there is life. From December to March, the Antarctic summer, 24-hour sunshine melts ice in the mountains, producing meltwater streams tha...

When plastics were introduced, they replaced glass, metal, paper and wood in many applications. That’s because plastic is a miracle. It’s cheap, light, can be formed into millions of products, and is incredibly durable. But these big benefits have led to a very big problem. Plastic pollution is now everywhere. And because it’s so durable, it’s not going away. Plastic pollution starts with us, mostly with single use plastics – bottles, cups, straws and bags, used once then discarded. Single us...

Gold has been valued by humans for at least 7,000 years. The earliest gold items were found in Bulgaria, from the 5th millennium BC. The first mines were likely in the ancient African kingdom of Nubia. Egyptians created great wealth, and great art, from gold. Gold is valuable because it’s so unusual. It’s very dense, even denser than lead. It’s very durable, yet also very soft. It’s the most malleable metal – we can roll it into sheets thin enough to transmit light. And it’s an excellent conduc...

One night in the mid-1800s, a naturalist in a boat saw something mysterious. The surface water was teeming with daphnia, zooplankton more commonly known as ‘sea fleas.’ The next morning, they had disappeared. The next night, they were there again. Where did they come from? Where did they go? For a century, this was a mystery. Then navy ships, using sonar to track submarines, found that the deep ocean bottom appeared far shallower at night – when it was moving upward! They theorized they were ...

On the island of Flores, in Indonesia, a team of anthropologists made a discovery so surprising, they kept it a secret for a year. In a cave called Liang Bua, they had uncovered 100 skeletal fragments of about 14 individuals – so small, that at first, they thought they might be the remains of children. But more investigation showed wisdom teeth and wear on bones that definitively marked these skeletons as adults – and a newly discovered species of hominin, just over 3 feet tall. They called t...

You may have seen sunscreens that claim to be “reef safe.” Which may have made you wonder, are sunscreens dangerous to coral? If so, could they be dangerous to me? Sunscreens come in two basic types. Inorganic, which are mineral based, using white zinc or titanium oxides to physically block the sun’s rays. And organic, using oxybenzone or octinoxate to absorb UV rays and turn them into heat. You’d think the organic ones would be healthier for humans. But some studies found they can penetrate t...

Mosses are small but mighty. We don’t think much about them, since they grow so close to the ground. But there are an estimated 22,000 species of moss, living on every continent including Antarctica, covering 2% of Earth’s surface. That’s the size of Canada! The soil under mosses globally can store 6 billion tons more carbon than bare soil. That’s more than the U.S. emits each year. After lichen, mosses are the second stage in what’s called the ‘primary succession’ – the conversion of a barren...