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.
102episodes
Episodes
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Geothermal Anywhere
2d ago00:02:00Tap to summarizeGeothermal energy, the heat of the earth, can be found under our feet everywhere on Earth.Historically, we’ve only been able to access it in a few places, commonly in hot springs. Much less commonly, in far fewer places, we find more intense heat, so close to the surface that it can be used to heat cities or generate electricity.That intense heat could be developed anywhere… if we could go deep enough, cheaply enough. And that’s always been the challenge: How to reach it, how to bring it back to the surface… and do so economically. New technology pioneered by the oil industry may be able to help.Over the last two decades, in pursuit of oil and gas trapped in shale, drillers have perfected longer and ever more precise vertical and horizontal wellbores, at economies of scale.Simultaneously, they’ve perfected fracturing techniques.These may finally allow very deep, precision wells into hot rock formations, where water could be circulated to bring up the heat. This could be done by fracturing the rock, or by running fluid through pipes.Instead of water, some companies are testing supercritical CO2, which behaves like a fluid and could transfer heat more efficiently. Costs for traditional drilling will remain a challenge. So other companies are experimenting with a high-powered laser to blast a deep hole.There are many obstacles yet to overcome. But the promise of widely available geothermal energy is inspiring innovative solutions.
Transcribe →Geologic Hotspots
2d ago00:02:00Tap to summarizeVolcanoes often form where tectonic plates collide or pull apart. But sometimes they’ll form in the middle of plates, due to geologic hotspots.A hotspot is a plume of hot mantle that rises from within Earth, and heats, expands and deforms the crust above it, to create mountains, volcanoes or volcanic islands.The classic example is the chain of Hawaiian Islands, which formed as the Pacific plate traveled across a hotspot.Scientists always thought hotspots were stationary, while tectonic plates moved over them. But new research from beneath the Indian Ocean has challenged that idea.There, an undersea mountain range runs north-south for 3000 miles, along the 90-degree East longitudinal line.This long ridge was formed by a hotspot—but scientists studying the age and geologic makeup of each mountain on the chain realized they grew faster than could be possible by the plate alone moving.The hotspot must also have moved, possibly by hundreds of miles.This simple discovery will cause us to rethink hotspots and volcano formation, all over the world.It may turn out that other well-studied hotspots, like those beneath Iceland and Yellowstone, are moving too. Which could help us better understand the geothermal and volcanic activity there.And that’s how science works. It’s always on the move—sort of like hotspots.
Transcribe →To Beard or Not to Beard
2d ago00:02:00Tap to summarizeHumans have lost most of our body hair, but the beard has stubbornly remained – though anthropologists can find no function for it.Perhaps that’s why men have been grooming it, or removing it, for thousands of years.Early cave paintings show men with smooth faces. Archeologists have found flint ‘razors’ they may have used to shave. And shell ‘tweezers’ they may have used to pluck off their beards. Ouch!The Egyptians were first to engage in elaborate shaving rituals. Facial hair was considered unclean, and men used copper razors or caustic chemicals to burn off their beards. Ouch again!Centuries later, Alexander the Great’s soldiers wore beards -- until he ordered them gone. Greeks reversed that tradition. For them, beards represented maturity and wisdom. The Romans reversed things again, and civilized men shaved or went to barber shops.Through the Middle Ages, beards came and went with the styles of influential leaders. Christian priests remained clean-shaven, to separate themselves from rabbis and Muslim clerics, who often had beards.In the 20th century, in the U.S. and Europe, shaving became synonymous with uprightness and business success. In the 21st century, things changed again, as beards reflect individual style and even environmental sustainability – avoiding the waste of disposable shaving products.If you’re wondering ‘to beard or not to beard,’ there’s no right answer. Wait a while and styles may change anyway!
Transcribe →Return of the Mammoth
3d ago00:02:00Tap 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!
3d ago00:02:00Tap 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
3d ago00:02:00Tap 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
3d ago00:02:00Tap 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
4d ago00:02:00Tap 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
4d ago00:02:00Tap 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
4d ago00:02:00Tap 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 →