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by Switch Energy Alliance
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.
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- Today2 min
Frozen in Time
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 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.
- Today2 min
Lost Underground City
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 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.
- Today2 min
Antarctic Dry Valleys
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 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.
- Today2 min
Ocean Plastic Pollution
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 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.
- Yesterday2 min
Gold From Earthquakes
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 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.
- Yesterday2 min
Earth's Greatest Migration
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 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.
- Yesterday2 min
Real-Life Hobbits
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 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.
- 2 days ago2 min
Sunscreen, Coral and You
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 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.
About EarthDate
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.
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