Podcast
EarthDate
Hosted by Switch Energy Alliance · EN
EarthDate is a short-format weekly audio program delivering concise, science-based stories about the Earth: its geology, environments, and the processes that shape our planet over deep time and today. Beginning in 2026, EarthDate is managed by Switch Energy Alliance and hosted by SEA's founder Dr. Scott W. Tinker. Together, we explore earth systems, natural resources, and their relevance to everyday life, with a focus on clear, accessible science education for broad audiences. EarthDate is written and directed by Emmy-winning filmmaker Harry Lynch, and researched by Lynn Kistler. We search for captivating stories to remind listeners that science can enlighten, educate and entertain.
129episodes
Episodes
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Return of the Mammoth
Jun 2200:02:00Tap to summarizeIf you believe the old cartoons, elephants are afraid of mice. But would a woolly mammoth be afraid of a woolly mouse? We may soon find out.That’s because scientists have recently used gene editing tools to tweak the mouse genetic code, adding genes from woolly mammoth DNA.The result? The woolly mouse, with long, shaggy fur and extra insulating fat. Fortunately, no tusks.The woolly mouse is the first step toward the de-extinction of the woolly mammoth itself.For that, the scientists will have to edit more genes in an embryo of the Asian elephant, the mammoth’s closest living relative. Then gestate that embryo in the womb of an elephant.Not everyone is a fan of the idea. Some have ethical concerns—just because we could bring them back, doesn’t mean we should. Others worry that de-extincted animals may struggle in modern climates, or invasively outperform existing animals.Mammoths disappeared after the last Ice Age, as Earth warmed and human hunters took a liking to mammoth barbecue.The de-extinction team believes they could bring them back, this decade. The question then is what to do with them?They’ve proposed creating herds of mammoths to release in Arctic regions like Siberia, to do what they once did—knock down trees, tramp down and compact the permafrost, to keep it from melting, and preserve the habitat of the tundra.If we can keep from re-extincting them, mammoths may one day roam wild again.
Transcribe →Hey, Bird Brain!
Jun 2200:02:00Tap to summarizeBirds have very large brains for their body size. New research is helping scientists understand how they work, and came to be.One part of a bird’s brain, the cerebellum, controls their amazing flight capabilities – their spatial awareness, allowing sudden direction changes through tree branches, or their ability to chart migration over thousands of miles.PET scans taken pre- and post-flight have shown very high brain activity in the cerebellum, especially the neural pathways connected to the eyes.CT scans of the skulls of modern birds and their fossil ancestors help explain how their brains evolved.The brains of early birds stayed the same size, as their bodies shrank. The brains of many bird families, like crows and parrots, then began to grow even larger.Island, nocturnal and insect-eating birds also grew larger brains, to manage difficult environments and chase flying prey.To control what birds do when not flying—building elaborate nests, singing complex songs, even solving puzzles—requires another part of the brain: the cerebrum.Other early bird fossils show that the cerebrum grew in size first, while the sophisticated flight anatomy, and the cerebellum to control it, developed later.Taken together, their cerebrum and cerebellum make a remarkable brain, which gives birds their even more remarkable qualities.So if anyone ever calls you a bird brain… well, say thank you!
Transcribe →Sprites and Elves
Jun 2200:02:00Tap to summarizeYou may remember that opposite electrical charges attract.If a positive charge builds up, it seeks to connect to a negative charge, to reach equilibrium.This is what creates lightning. As explained in a prior episode, it’s generated by the static electricity of water vapor and ice molecules rubbing against each other. Billions and billions of molecules can produce a whopping charge.Positive and negative charges build within the cloud, but they’re separated by air, which is a poor conductor. But once the charges are large enough, they overcome that resistance and connect as lightning—within the cloud or to Earth.Sometimes, though, a powerful charge builds in the top of the cloud, and rather than striking down, it seeks equilibrium by going … up!The charge leaves the top of the cloud and explodes into the atmosphere in what’s called a Transient Luminous Event, or TLE.There are several types, called Sprites, Blue Jets and Elves. That’s ELVES—Expanding Light emission from Very Energetic Sources. They take the shapes of columns, glowing rings or giant ‘jellyfish.’ But they last just a fraction of a second.Eyewitnesses saw TLEs 300 years ago. But it wasn’t until the advent of super high-speed video that scientists could capture their remarkable images to study them.Another reminder that there are still many things to discover, right here on—or just above—Earth.
Transcribe →Rare Earth Recovery
Jun 2200:02:00Tap to summarizeRare Earth Elements, or REEs, are a group of 17 trace metals that play important roles in the electronics we rely on daily. Their properties are so unique, they’re not replaceable.But their current supply is almost completely controlled by China, which creates shortages and security challenges. So, researchers are looking for domestic sources—and have found a surprising one: coal ash.When coal is burned at a power plant, it’s reduced to gases and about 10 percent of its weight in ash. In that ash, the trace metals from the coal become concentrated.Scientists from the Bureau of Economic Geology first recognized that coal ash could be a source for REEs.When they surveyed the ash produced by U.S. coal plants since 1950, they found 35 million tons that could be available for REE recovery. It’s currently stored in landfills and retaining ponds, mostly near the power plants.There are different concentrations of REEs in the ash. Eastern coal has the highest concentration, and Western coal the lowest—but western coal’s simpler molecular structure could allow more REEs to be recovered.The next step is to set up pilot projects to test the process, its energy requirements and environmental impacts.The preliminary studies look promising, offering a chance to build a domestic industry in Rare Earth Elements, while building better long-term storage for the coal ash. A technology win-win!
Transcribe →Swamp Architects
Jun 2100:02:00Tap to summarizeOn the east coast of the Yucatan Peninsula lie the wetlands of Belize. Swampy, hot and full of mosquitoes, these are unappealing places.But when they dry out each season, visitors noticed earthen banks that cut across the marsh.They thought these were water gathering facilities created by the Maya, who populated Belize centuries ago.Then carbon dating revealed they were at least a thousand years older. What could they be?When extended drought dried the swamps long enough for detailed field work, archeologists used new technology to learn more.With lidar—laser technology that can create detailed topographic images—they could ‘see through’ swamp vegetation. With drones, they could photograph difficult areas to reach.Combined, these allowed them to build a detailed 3D map of the area, revealing a vast, zig-zag network of channels and pools.In the wet season, when waters rose, ocean fish and other marine life would stream into the wetlands to spawn. When the dry season came, the channels would guide the fish into holding ponds for further growth and easy capture.This was a sophisticated system of aquaculture, centuries before the Maya.The scientists estimate it allowed as many as 15,000 people to live in and around the swamps, which they had re-engineered for their needs.These clever swamp dwellers may be the cultural predecessors of the great civilizations of Mesoamerica.
Transcribe →Super Sponges
Jun 2100:02:00Tap to summarizeYou 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 water around reefs where they live; some even filter out dangerous elements.A few species sequester high levels of arsenic, barium and molybdenum enough to be toxic to other lifeforms.This has given ecologists the idea to grow colonies of sponges at the mouths of polluted rivers, to make the water safe.Sponges manage these toxins with symbiotic bacteria that bond to the elements and make them inert. Medical researchers are investigating ways to do the same in humans.Many other useful medical compounds have come from sponges.They produce spongothymadine, which mimics a building block of DNA, to trap viruses.Biotech companies have used spongothymadine to produce drugs for HIV and cancer, with many more sponge-inspired treatments in development—for antibacterial, antifungal and anti-inflammatory medications.An amazing array of benefits from the simple, super sponge.
Transcribe →Hydrogen from Rocks
Jun 2100:02:00Tap to summarizeYou may have heard that hydrogen could be a fuel of the future, with lower carbon emissions than any we’re using today.When it’s burned, it produces only water vapor and a lot of useful energy as heat. That sounds pretty good.And hydrogen is the most abundant element in the universe. That sounds good too.But nearly all hydrogen on Earth is bound up in other compounds, like water. Or natural gas—methane—which is one carbon atom and four hydrogens.Today, we get most of our hydrogen by splitting that carbon atom off methane, leaving the hydrogen behind.But that means making it also makes carbon emissions. This has researchers looking for alternative methods.The most common is electrolysis. An electric current is run through water, which splits the atoms, releasing oxygen and hydrogen. But it costs a lot of money because it consumes a lot of energy—more than is carried by the hydrogen itself.There’s another, naturally occurring process that makes hydrogen deep within Earth. When water contacts iron-rich rocks, like olivine and pyroxene, it oxidizes and releases hydrogen gas, and heat.Scientists at the Bureau of Economic Geology are experimenting with catalysts that could speed up this natural process, but near the surface. This has the potential to release large amounts of hydrogen—without consuming much energy or releasing CO2.If successful, this process could make hydrogen a fuel of the very near future.
Transcribe →Earth's Rarest Mineral
Jun 2000:02:00Tap to summarizeWhat’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 to the local gem market.There, Dr. Kyaw Thu, a gemologist, picked it up. It was heavier than most metals. And it had a slightly metallic sheen. He bought it for a few kyats and took it to his workshop.There he began to study it—and found that it was a crystal compound of two rather rare metallic elements, bismuth and antimony. Surprised, he began to look for other specimens in the literature, and there were… none.Not a single other specimen of this mineral had been identified anywhere on Earth, ever.He submitted his finding to the International Mineralogical Association, who officially recognized it as one-of-a-kind—and named it after him: kyawthuite.If you’d like to see it, the crystal now resides in the Los Angeles Natural History Museum.What’s such a gemstone worth? Well, with no others to set a market value, it’s simply … priceless.
Transcribe →Sexy and Dangerous
Jun 2000:02:00Tap to summarizeAnimals 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 widow spider. Or the high contrast stripes on bees, wasps and skunks.But bright colors also make them more visible to predators; so how did this trait develop?Scientists looked at three coloration schemes across more than a thousand species, and found they fell into three groups:Camouflaged. Brightly colored. And Hidden-signal—which flash colors only when threatened.Their research suggests that some hidden-signal types developed chemical deterrents. Then, as generations passed, both their poison and coloration increased, spreading to other parts of the body until a brightly colored, highly venomous species emerged.Still, many species remained camouflaged, but developed strong poisons. While others evolved to mimic the dangerous coloration of their peers, but remained harmless. It can be hard to know which is which.So, if you ever see a brightly colored or a well-camouflaged wild animal, best to look but don’t touch.
Transcribe →Plants That Eat Bugs
Jun 2000:02:00Tap to summarizeTrue 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 an electrical impulse and the jaws snap shut. Then enzymes slowly digest the prey.The Sundew has tentacles with glistening drops on the ends that look like nectar. But insects that land to partake find they’re actually sticky digestive fluid. The Sundew’s tentacles wrap around the bug and feast.The Pitcher Plant looks like its namesake, with a smell that attracts insects. But if they crawl inside, the walls are too slippery to escape.Waiting at the bottom: more digestive enzymes that will melt them alive.And if that’s not gross enough… the ‘toilet plant’ looks like its namesake. It produces a sweet nectar to lure rodents or bats.When they come to drink, extended beneath them is a bowl to catch whatever they excrete. The plant gets all its nitrogen and other minerals from animal droppings.So, if you think eating bugs is unappetizing, well, it could be worse.
Transcribe →