EarthDate

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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.

  1. 2 HRS AGO

    Giraffes Have High Blood Pressure

    Giraffes are fascinating animals. They have the same number of vertebrae in their necks as humans do—seven—but each one is nearly a foot long. They have long, purple tongues too—nearly two feet—that can grasp things as easily as a monkey’s tail can, which they use to pull leaves and fruits from high branches. All four giraffe species are covered in spots. And each individual’s spots are as unique as a fingerprint. But the most fascinating thing about giraffes...is their cardiovascular system. Their head is so high up that to deliver normal blood pressure to their brain they must generate twice normal pressure at their heart. Enough blood pressure to kill a person. They do that with a heart that’s two feet long and weighs up to 25 pounds. They also have specialized one-way arteries. When a giraffe tilts its neck down, valves in its jugular close, storing up to a liter of blood, to keep it from flooding the brain. When the giraffe lifts it head back up, the blood rushes out of the jugular back to the heart, pressurizing it so it can pump blood all the way back up the neck to the brain. Arteries in the legs constrict to stop blood from pooling in the feet, and special connective tissue acts as natural compression socks. The giraffe’s miraculous blood pressure control system is still not well understood by scientists. But they’re studying it to see if it might one day help humans manage our own high blood pressure.

    2 min

  2. 2 HRS AGO

    Raising Hail

    Hail is created when rain starts falling up. This usually happens in the spring, in middle latitudes, when tall clouds form over warm updrafts. In the cold upper reaches of the cloud, water condenses around nuclei, like dust particles, dirt, or salt crystals, to form droplets of rain that begin to fall to Earth...but then are pushed back upwards by the updraft. The rain droplets tumble within the cold center of the cloud, falling down and being pushed back up repeatedly, where they collide with other droplets and begin to freeze, turning into tiny hailstones. More water droplets and water vapor freeze around them, and the hail grows in size and weight. If the updraft is strong, the hail will continue to be suspended in the middle of the cloud, growing until it’s too heavy to stay aloft. When the hailstones do fall, they can be destructive. Small hail weighs less than an ounce. But even that can cause billions of dollars in damage, pummeling crops, denting cars, and destroying roofs. However, hail as large as a softball has been reported, falling at more than 100 miles an hour. Giant hailstones like this have occasionally even killed people. So, if you see hail larger than golf balls falling, take shelter underground, or inside a building away from windows, which can break. Because, while a little water never hurt anyone, it can be dangerous as hail.

    2 min

  3. 2 HRS AGO

    Treasure on the Seafloor

    At the bottom of the ocean lies a treasure. But recovering it could be technically difficult, geopolitically challenging, and environmentally damaging. Eighty three percent of the ocean is a mile deep, or much more, making the deep ocean the largest environment on Earth, covering 115 million square miles. Down there, like in the Amazon, species diversity is high. There may be thousands of species we have not yet identified. Down there, also, are polymetallic nodules and crusts, formed of iron and manganese, and in smaller amounts, cobalt, lithium, molybdenum, rare earth elements and other valuable metals that precipitate out of seawater, very slowly, over millions of years. Many of these metals are used in new energy technologies, like batteries, so companies and countries are considering recovering them. But it’s complicated. Most of the deep ocean is in international waters. No one’s quite sure how to regulate or share revenue from mining there. And the deep ocean is a poorly understood environment. Mining could kill many creatures and damage seafloor ecosystems. So far, no permits have been issued. But there is pressure on international authorities to do so, as today’s supplies of many of these materials are limited. Efforts to mine the deep ocean, responsibly and sustainably, may be an area of dispute—and opportunity—in the future.

    2 min

  4. 1D AGO

    Britain’s Stone Age Mines

    The gleaming White Cliffs of Dover have dark seams of flint within them that were the target of some of Britain’s first mines—more than six thousand years ago. The white cliffs are made of nearly pure chalk, the remains of phytoplankton, tiny floating algae. These phytoplankton lived here in warm Cretaceous seas. When they died, their spherical bodies fell apart into the hard plates that covered them. The microscopic plates, made of calcium carbonate, sank to the seafloor. There they formed a layer of white mud, at a rate of just half a millimeter per year. But over 30 million years, that white sediment layer reached nearly two thousand feet thick. Its weight compacted it into the chalk we see today. The main consumers of these floating algae were radiolarians, tiny zooplankton whose bodies were made not of calcium but silica. Once they died, and were compacted for millions of years, the silica in their remains formed layers of flint in the chalk. Though flint is a form of quartz, it’s nearly as hard as a diamond. It can be chipped to have very sharp edges, which Stone Age humans used to make blades and hunting points. It was so valuable that Neolithic tribes would dig mine shafts down through the soft chalk to reach a strip of flint, then bring it to the surface to work into tools. These mine shafts, and the tool making sites around them, may be Britain’s earliest industry and one of the reasons that human population grew here.

    2 min

  5. 1D AGO

    Dam Good

    Beavers are amazing rodents. They have long teeth that never stop growing; they control their length by gnawing on wood. They have fat-insulated bodies, webbed feet, and a large flat tail—which make them clumsy and exposed on land but quick and graceful in the water. Most importantly, beavers cut down trees to dam streams and rivers to make their homes. To many humans, these activities seem destructive. But the ponds and wetlands they create are essential for hundreds of other species that have coevolved with beavers over the last 10 million years. These include fish and insects, water birds, amphibians and reptiles, large grazing animals, and a multitude of plant species. Beaver ponds and wetlands provide food, water and shelter for many of these species—and create huge benefits for the forest: The ponds protect the woods from fires. Their surface water slowly drains into and recharges the water table. They filter out particulates to purify streams. They slow the progress of, and can even stop, floods. And serve as water repositories in times of drought. A century ago, trappers had hunted beavers nearly to extinction, for their furs. But around 1900, laws were enacted to protect them, and their population has since rebounded. Thankfully, beavers now occupy nearly all of their previous range, shaping and improving the landscape from Canada all the way down to northern Mexico.

    2 min

  6. 1D AGO

    Invisible Forces Shape Waves

    When you watch waves crash on the beach, you’re seeing the visible end result of many invisible forces. Waves are formed near or very far from shore, usually by wind—the first invisible force. As wind blows over the sea, surface friction transfers its energy to the water. How fast, how far, and for how long the wind blows determines how much waves grow. When the wind stops blowing, the waves stop growing—but they don’t stop traveling. A wave is not actually water traveling but instead another invisible force: energy traveling through the water. When a wave passes, water molecules lurch forward then back, coming to rest in nearly the same place. But that movement transfers energy to the next water molecule...and so on. Uninterrupted, this wave energy can travel thousands of miles through open ocean, sometimes for more than a week, before finally reaching a shoreline. As the water grows shallower, another invisible force comes into play: friction against the ocean bottom, which slows the base of the wave. But the top of the wave keeps moving at its original speed, eventually crashing forward over the wave base. The shape of that wave break is determined by the unseen topography below it. In some places, deep undersea canyons channel and concentrate wave energy as it reaches shore, to form some of the largest waves in the world. Spectacular sights, formed out of sight.

    2 min

  7. 1D AGO

    Swelling Seas

    Since the peak of the last Ice Age, Earth’s ice has been melting, and sea level has risen nearly 400 feet! But only recently do we have the technology to carefully measure it. For the last 20 years, a network of satellites and nearly 4,000 robotic floats have been measuring temperature and surface elevation of the global oceans. They’ve found that the surface of the ocean has warmed an average of 1 degree Fahrenheit in that time, and average global sea level has risen 3.5 inches. While this is within the normal rate of sea level rise for the past 8,000 years, we can now better understand what’s happening: Warming seas have contributed to the melting of ice sheets in Antarctica and glaciers in Greenland. Their meltwater is responsible for about 2.3 inches of that sea level rise. But the other 1.2 inches comes from a property of water itself. Water expands as it warms because molecules bump up against each other more frequently, causing an increase in volume. Meaning that, as oceans have warmed, they’ve swollen in their basins and slowly crept onto the land. Oceans act as heat sinks to moderate global temperatures swings, and researchers estimate they have absorbed 90 percent of the warming that Earth has experienced over these past 20 years. As our planet and oceans continue to warm, there will be more sea level rise, not just from more meltwater, but further swelling of the sea.

    2 min

  8. 2D AGO

    Carlsbad Caverns

    Carlsbad Caverns National Park is a very rare place. Its main room is the largest cave chamber in North America, covering more than eight acres. And its cave formations are unsurpassed anywhere. It’s also rare because it was created not by carbonic acid percolating down through the soil but by sulfuric acid coming up from below. Around 20 million years ago, hydrogen sulfide gas began to migrate underground from oil deposits in the Permian Basin of Texas, toward the exposed fossilized reefs near what is now Carlsbad, New Mexico. There, the hydrogen sulfide gas rose to meet the water table. It combined with oxygen to create sulfuric acid and began to dissolve the limestone that forms the Permian reef. Over the ages, as the water table rose and fell, the sulfuric acid worked on shallower and deeper layers, creating hundreds of caverns, some thousands of feet below ground. Around a million years ago, erosion connected the caves to the surface. Mineral-enriched water began to trickle in and, drop by drop, over millennia, formed spectacular crystal formations of calcite, aragonite, and gypsum. Seven thousand five hundred years ago the area began to dry up and the cave formations stopped growing. But they’re preserved there today in all their glory—waiting for you to make the trip to Carlsbad Caverns, to see some of the most stunning geology in the world.

    2 min
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About

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.

Information

  • Creator
    Switch Energy Alliance
  • Years Active
    2K
  • Episodes
    300
  • Rating
    Clean
  • Copyright
    © Copyright 2026 EarthDate
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    EarthDate