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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What Does a Mummy Smell Like?
Jun 2000:02:00Tap to summarizePause 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 the heart were removed and placed in special jars. The lungs, liver, stomach and intestines were each preserved in their own ceramic resting places.The body was then dried using a mixture of ash and baking soda to preserve it and stop most bacterial decay.Then it was wrapped in many layers of bandages, and finally coated in fragrant tree resins, which would bond with the linen.Scientists analyzed the many resins found in the ancient workshop, and discovered they came from plants across the vast Egyptian empire and its trading routes into India, Africa and the Philippines.They went so far as to work with modern perfumers to recreate the smell of the mummy embalming blend. They combined resins from damar, elemi, cedar and pistachio to create a fragrance they dubbed, wait for it, “Scent of Eternity.”But if you’re dying to smell like a mummy, unfortunately, the perfume is not yet on the market.
Transcribe →Pasteur's Rabies Vaccine
Jun 1900:02:00Tap to summarizeRabies 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 was no treatment.Then came Louis Pasteur. First, he invented the process to sterilize milk and other liquids, by heating them near boiling to kill bacteria.Next, he focused on diseases, beginning with cholera. He cultured it in a lab, then discovered that chickens injected with older strains weren’t affected by the disease – and were immunized against new strains.He developed a similar treatment for anthrax, which often infected livestock, then moved on to rabies.He found that the dried spinal cords of animals killed by the disease contained a weak version that could be injected to immunize against the live virus.Thanks to Pasteur, rabies has been almost completely eradicated in the US, with several organizations aiming for zero cases worldwide by 2030.Do your part by vaccinating your pets, and yourself, if bitten, or traveling to areas where rabies is still endemic.
Transcribe →Sulfur Stinks
Jun 1900:02:00Tap to summarizeCow 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 of its most repellent aromas. Like a skunk’s spray or the eye-watering fumes of freshly chopped onions.The ancient Greeks burned sulfur as a fumigating pesticide to kill insects and rodents. When combined with water, sulfur fumes become acid rain.But sulfur is not all bad news. In fact, it’s essential to life on Earth.Sulfur is a key component of two essential amino acids, cysteine and methionine, which are building blocks for proteins.Cysteine helps produce collagen and beta-keratin, proteins found in skin, hair and nails. Methionine protects cells from damage.Plants too require sulfur, to make chlorophyll and fix nitrogen, which is why it’s used as fertilizer.Legumes use sulfur to make their protein. Cruciferous plants, like cabbage and broccoli, get from sulfur their signature flavor – and of course, their stinky aroma.
Transcribe →Energy Born of Earth
Jun 1900:02:00Tap to summarizeAs 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 hydrocarbons through time. They’re essentially solar energy converted through photosynthesis and geologic processes into … Earth resources.As long as we have a sun, sunlight is renewable. But the solar panels to collect it are rebuildable. They too are made from Earth materials—glass, silica and aluminum—then after a couple decades need to be built again, of more materials.Hydroelectric dams are powered by rainfall, from Earth’s water cycle, but built of giant volumes of concrete and steel.Drilling, mining and manufacturing, for all these energy systems, consume huge amounts of Earth materials, water and land.Even the energy that powers our bodies comes from Earth; plants of course, but also fertilizer, farm equipment, transport trucks and grocery stores that are made of, or powered by, Earth resources.We live on a generous planet that takes care of us. Let’s make sure to return the favor.
Transcribe →Whale Words
Jun 1700:02:00Tap to summarizeIn 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 studying the dialogue of a clan of sperm whales in the Caribbean for many years.Sperm whales communicate with rapid clicks, produced by blowing pressurized air through their nasal cavities, which is then amplified by a resonating organ in their heads.They can vary the number and tempo of the clicks to form complex streams.Scientists recorded thousands of click streams, then used machine learning to uncover 156 patterns shared by individuals in the clan – like a vocabulary of whale words.However, they still have no idea what these words could mean. So, the next step is to attach cameras to the whales to try to connect actions to the words.If they can understand this whale clan’s vocabulary, they may be able to communicate with them…And perhaps decipher the language of other whales, other lifeforms on Earth, maybe even signals from beyond our planet.
Transcribe →History of Radio
Jun 1700:02:00Tap to summarizeA 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 quickly changed.In 1920, the first commercial station went on air in Detroit. Within four years there were 600 stations across the country, as sales of home radios boomed.In 1927, the government created the FCC to parcel out different wavelengths to radio stations.In the 100 years since, those grew to 15,000 stations in the US, among 44,000 worldwide, delivering some famous radio moments that united us all.FDR guided America through the Depression with his radio fireside chats. Rock and roll was born, largely as a radio phenomenon. Millions listened to Neil Armstrong’s first words from the moon.Today, 92% of Americans listen to radio weekly. Worldwide, people average 104 minutes a day! And you just enjoyed two of them.
Transcribe →Did Earth Have Rings?
Jun 1700:02:00Tap to summarizeEarth 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 findings suggest that Earth may once have had rings too, around 460 million years ago.Scientists found a ring of meteorite impact craters that date to this period, circling Earth’s equator.They theorized that an asteroid passed too close to Earth, was trapped then broken up by gravity. The debris scattered into a ring, which eventually fell to Earth around the equator.Rings around Earth may also have formed our moon.The leading hypothesis of the moon’s formation has been that a single large asteroid or other planet crashed into Earth and knocked off a chunk that became the moon, as described on another EarthDate.A new hypothesis is that multiple large collisions produced debris rings, which coalesced into moonlets. As these drifted farther from Earth, they merged into a single moon.Or it could be something else entirely. It’s amazing how much we still don’t know about the moon and our planet itself.
Transcribe →Ocean Plastic Pollution
Jun 1600:02:00Tap to summarizeWhen 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 use plastics make up half of all plastic waste.Very little is recycled. The plastic that doesn’t go to landfills may be shipped to other countries, or scattered as litter, and eventually gets washed into rivers and oceans, where it stays.There’s now a spinning garbage patch of plastic in the Pacific Ocean the size of Alaska!Nearly all sea turtles and large ocean mammals, like whales, have plastic waste stuck in their digestive systems.Nearly all seabirds, too. Small bits of plastic, which they mistake for prey, can eventually fill their stomachs, killing them.Plastic pollution is in all of us too. It breaks down into tiny particles called microplastics, which get into our water supply and food.But each of us can do something about it – starting by avoiding single use plastics.We caused the plastic pollution problem; it’s up to us to fix it.
Transcribe →Antarctic Dry Valleys
Jun 1600:02:00Tap to summarizeThe 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 that trickle into the valleys. They fill shallow, ice-covered lakes, in which microorganisms thrive.When the water evaporates, some of those micro-critters continue to live in brine pools. Others persist in the soil.Others live inside the glaciers that surround the valleys. That’s because trapped within them are the remnants of an ancient ocean. The water is too salty to freeze, and devoid of oxygen.But the microbes metabolize sulfur and iron, which may come from the glaciers scraping over iron-rich rocks as they move.One of the glaciers terminates in the dry valleys, where it secretes its red brine at Blood Falls.Scientists believe this frigid hellscape, blasted by wind and blistering UV rays, is the closest environment on Earth to Mars.So they’re studying it, to learn how life can survive here -- and how it might survive on the Red Planet itself.
Transcribe →Lost Underground City
Jun 1600:02:00Tap to summarizeSixty 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 called tuff. On the surface it eroded into tall spires called fairy chimneys. Underground, water seeped in to form caves, which early cultures excavated further.Around 3,000 years ago, the Hittites began to carve the underground city of Derinkuyu. It was expanded by Christians throughout the Middle Ages.In the cool, lowest levels they stored grain and wine. In the middle levels they kept livestock. The highest levels were residences. A network of ventilation shafts brought fresh air to all.The underground city provided shelter from the weather, and from invaders.Central Turkey, at the crossroads of the Silk Road, was a frequent stop for marauding armies. Derinkuyu residents rolled massive stone doors across entrance tunnels to protect inhabitants.From 1500 AD until today the city was forgotten. But it’s now a UNESCO protected site, and a remarkable window into the past.
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