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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Frozen in Time
Jun 1600:02:00Tap to summarizeAmber 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 within it.Many of these are too delicate to be preserved in the fossil record, and are only available to scientists in amber.Specimens have been found around the world. Amber erodes out of the Baltic seashore, and can be mined in Myanmar, Canada, the Dominican Republic and many other places.Collectors and researchers have found flies, spiders eating those flies, and mites clinging to the legs of those spiders. Lizards and salamanders. Feathers from birds, and from dinosaurs.Even a nearly entire baby bird, complete enough that researchers could study the structure and color of its skin and feathers -- even the lice that lived on them.In fact, amber preserves tiny insects and arachnids almost like they’re modern specimens, allowing scientists to examine bugs that went extinct 100 million years ago as if they were alive today.This makes amber not just a beautiful gem, but a valuable scientific tool.
Transcribe →Gold From Earthquakes
Jun 1500:02:00Tap to summarizeGold 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 conductor of both heat and electricity.Gold miners noticed 2 other curious properties. Most gold is found in quartz. And it’s often found in earthquake zones.Scientists wondered, could the two be connected? So, they set up an experiment to find out.They immersed quartz crystals in a solution of water and gold ions. Then they subjected the tank to 20 hertz soundwaves, simulating an earthquake.The sound pressure triggered the piezoelectric properties of quartz – when subjected to physical stress it produces an electrical current.The electric charge drew the gold out of the water solution to clump on the quartz. That gold carried the current, because it’s such an excellent conductor, and drew more gold to clump onto it.This may explain why the largest gold nuggets are found on quartz. And, if we could attract it to an electric current, it just might be a new way to prospect for gold.
Transcribe →Real-Life Hobbits
Jun 1500:02:00Tap to summarizeOn 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 them Homo floresiensis, after the island. But they nicknamed them hobbits, and the moniker stuck.This community of hobbits had lived on Flores from about 100,000 years ago until just 50,000 years ago, then went extinct.More recent discoveries on the island found the hobbits’ even smaller ancestors, who arrived between 1 million and 700,000 years ago, and quickly shrank in size, in a process called island dwarfism, where species get smaller in response to limited resources.Indonesia also once had dwarf elephants and other creatures.But the presence of the hobbits, at a time when Homo sapiens were already well established in Africa, Europe and the Middle East, and venturing into Australasia, shocked the anthropology world.And reminded us that, for hundreds of thousands of years, there were several kinds of successful humans on Earth -- before our kind became the sole survivor.
Transcribe →Earth's Greatest Migration
Jun 1500:02:00Tap to summarizeOne 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 getting a false reading, as the sonar bounced off swarms of sea creatures, rising in the water column.Scientists took a trawler out at night and brought up nets full of small fish, crustaceans and jellyfish. The navy operators were right. They had discovered the DVM, the Diel Vertical Migration.Further investigation revealed what was happening. Phytoplankton – tiny floating algae – stay near the surface during the day to collect sunlight for photosynthesis.Small creatures that eat phytoplankton hide in deep water during the day, to avoid being eaten themselves.Then at night, they migrate to the warmer surface to feed and mate. Large predators, even sharks and whales, follow them up. As dawn approaches, they all sink back into the deep.It turns out this happens in every ocean, in every lake, everywhere on the planet. It’s the largest migration on Earth – and amazingly, it happens every night.
Transcribe →Mighty Moss
Jun 1400:02:00Tap to summarizeMosses 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 environment, like a lava field, into one that can sustain life.With enough water, moss will continue to grow, decay and grow again, forming the basis of soil. And within the moss, other lifeforms begin to grow, like fungi and ferns. But also mites, tardigrades and nematodes. Under a magnifying glass, mosses look like miniature forests.And they’re hardy. One desert species in China can tolerate some of the lowest and highest temperatures on Earth.To test its toughness, scientists exposed the moss to even greater temperature extremes, froze and dehydrated it. The moss rebounded without issue.They even subjected it to radiation that would be lethal to mammals. The moss just grew faster.The idea behind these tests was to see if this particular moss could one day be sent to Mars. One of Earth’s lowliest species just might green the red planet.
Transcribe →Sunscreen, Coral and You
Jun 1400:02:00Tap to summarizeYou 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 the skin, enter the bloodstream, and may interfere with endocrine systems.In corals too, some studies showed that very high concentrations of oxybenzone sunscreen make them eject the symbiotic algae that lives within them. Without the algae to conduct photosynthesis, the corals bleach and may die.While you should always protect yourself from the sun, you may want to avoid sunscreens with oxybenzone or octinoxate. And avoid spray or powder sunscreens as they can be toxic when inhaled.The lowest risk, and most effective sunblock, is to cover up or get out of the sun mid-day. And use mineral-based sunscreens when needed.If you want to protect corals, ironically one of the best things you can do may be to visit and admire—though never touch—them.Your tourist dollars encourage local authorities to protect their reefs from fishing and overuse, and preserve them for future generations—of visitors, and coral.
Transcribe →World's Deadliest Animal
Jun 1400:02:00Tap to summarizeWhat’s the world’s most dangerous animal?Sharks? Nope, they bite only 70 people a year, with just six fatalities. Poisonous snakes? They kill about 50,000.But far and away the most dangerous is the mosquito. It kills a million people a year, and sickens 250 million more! But we may be able to stop it, with an even tinier creature.There are 3,000 species of mosquito. Different ones can carry malaria, West Nile virus, Zika, yellow fever, dengue, Japanese encephalitis, and more.They don’t cause these diseases, but instead bite an infected person, then pass it to others.Some of these diseases, like malaria, have medicines to prevent and treat them. Others like dengue, don’t.But scientists may have found a novel solution – infecting the mosquitoes themselves, with bacteria called Wolbachia.Wolbachia exist symbiotically in about 50% of insect species. When introduced to mosquito populations, they consume essential molecules within the insect, like cholesterol -- the same thing that Zika and dengue rely on.This means those diseases can’t survive within the mosquito and can’t be transferred to more humans.Wolbachia don’t kill the mosquitoes, and are found to be harmless to humans and other creatures that depend on mosquitoes for food, like birds and bats.A microbiological treatment for a global disease problem.
Transcribe →Fibonacci Sequence
Jun 1400:02:00Tap to summarizeAmazingly, the structure of most living things, and many other things as well, conforms to one sequence of numbers.It was described in the 1200s by Italian mathematician Leonardo Pisano, also called Fibonacci, working from earlier Indian ideas.The Fibonacci Sequence is 1, 1, 2, 3, 5, 8, 13 and onward – where the first two numbers, one and one, add up the next number, two. The next two numbers, one and two, add up to the next number, three. And so on.Most flowers have three, five, eight or thirteen petals.Spirals found in nature – seeds in a flowerhead, snail shells, even hurricane clouds – expand outward according to the sequence.Scientists looked at 12,000 spirals in different species and found that 90% adhered to the Fibonacci Sequence.But we’re not sure why. The pattern must confer some kind of structural advantage, enough that it continues to persist in newly formed species.Human designers often use the Fibonacci Sequence intentionally when designing art or architecture.Or unintentionally, by mimicking the geometries of nature.You can see it the next time you pick up a pinecone, eat an artichoke, or look in the mirror.The human body has one head, one torso, two arms, with three segments each, ending in five fingers.Efficient and elegant, the Fibonacci Sequence is the shape of nature.
Transcribe →Grand Teton National Park
Jun 1300:02:00Tap to summarizeGrand Teton National Park contains North America’s youngest mountain range: the towering “Tetons.” While the range formed by extension along a tectonically simple “normal” fault, the Teton Fault is unique because it has moved nearly 33,000 ft (10 km) in just ten million years. Preserving astounding natural beauty and a human history stretching back at least 11,000 years, the national park was first established in 1929.
Transcribe →Extinct Tree, Alive Today
Jun 1300:02:00Tap to summarizeThought to have been extinct for over 2 million years, a cluster of Wollemi pine was discovered by hikers in a secluded canyon outside of Sydney, Australia in 1994. Guarding this area from humans and fire along with cultivation and conservation efforts by botanical gardens have safeguarded this unique species. Now, advances in decoding the Wollemi pine genome may provide the secret to successfully preserve this critically endangered species.
Transcribe →