EarthDate

Switch Energy Alliance
  • 0.0 (0)
  • EARTH SCIENCES

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. 6H AGO

    Cooler in the Mountains

    Here’s a riddle: If heat rises, and mountains are closer to the sun, why are they always colder? The answer may surprise you. The heat of the sun can’t actually radiate through space. There would need to be particles of some element to conduct its heat; but space is a vacuum. Instead, the sun emits electromagnetic energy: ultraviolet, visible and infrared light, X-rays, and radio waves. When this solar radiation finally meets Earth’s surface, it warms it. And that radiates heat back upward, warming the atmosphere from the bottom up. So is that why it’s warmer lower and cooler higher? Not exactly. It has more to do with air pressure. Like all gases, the air in our atmosphere is a poor conductor—because it’s not dense with particles. However, the atmosphere does have mass. And its weight bearing down on the air at the surface compresses it more than the air at altitude. The compressed air is denser with molecules, which are more likely to collide, and these collisions produce heat. That means the air near the surface is not only better able to conduct Earth’s reflected heat but generates its own heat because it’s dense. This hot air can indeed rise. But as it does, the atmospheric pressure decreases, the air expands, and it cools. So, even though they’re closer to the sun, thin air in the mountains keeps them colder than the thicker air in the lowlands surrounding them.

    2 min

  2. 6H AGO

    Pterosaurs

    If things had worked out differently, you might see a tiny pterodactyl on your windowsill instead of a modern bird. That’s because pterosaurs evolved more than 80 million years before the earliest birds, with many of the same characteristics. Pterosaurs had hollow bones, some with an even more sophisticated structure than birds; it’s one of the things that allowed them to grow to such immense size: the largest pterosaur was bigger than an F-16 fighter jet, with a wingspan of 33 ft. These gigantic beasts were able to launch themselves because they were quadrupeds, which allowed them to run to get airborne. Pterosaurs may also have been warm-blooded like birds, as suggested by pelts of hair-like bristles found in the fossil record. They appear to have had similar social structures to birds: they reared young in nests, and some species appear to have traveled in flocks. Many pterosaurs sported eye-catching crests like today’s birds. Theirs were made of bones and skin, but are thought to have served the same purpose of attracting mates. Sharp-toothed predators, peg-toothed clam crackers, filter feeders living on lakes, pelican-like ocean fishers. Insectivores the size of today’s cardinal. Swoopers, stalkers, and scavengers. They did it all, they did it well, and they did it first! Why did more than 200 species of pterosaurs perish when the Chicxulub asteroid struck, allowing birds to take their place? It’s a mystery that scientists are still working to solve.

    2 min

  3. 6H AGO

    Beach Reading

    Here’s a great story to read on the beach, but it’s not on your summer book list. Every beach is a mystery. Read the clues right and they’ll tell you about the area’s ocean floor, sea life, and geology. You can start with the usual suspects: waves. They make or break a beach. Gentle slopes and slow-rolling waves produce wide beaches and shallow, sand-rich bottoms extending way off shore. Steep slopes and tall, angular waves that crash hard rob the beach of sand, keeping it narrow and rocky. Now scoop up some sand for a closer look. Fine, rounded grains that look mostly alike mean the beach is made of rocks and minerals from far away, broken down over long time frames as they traveled in rivers or ocean currents. Pebbly, angular sand grains with lots of diversity come from nearby coastal headlands or fast-moving rivers. White sand could be quartz, or limestone from nearby cliffs, or ground-up seashells, suggesting an ocean healthy with mollusks and snails. Pink sand could be ground-up coral, indicating offshore reefs Black sand is made of obsidian or basalt, like on some beaches in Spain. Green beaches mean volcanic rocks are eroding, concentrating olivine in the sand, as you can find in Hawaii. With a keen eye, there’s a great deal to uncover on the beach. For more clues, visit EarthDate.org.

    2 min

  4. 6H AGO

    Fire Weather

    In another EarthDate, we talked about ways to prevent wildfires. Now, we’ll talk about what’s encouraging them. In a warming climate, the air holds more moisture. It draws more water from plants, making them drier and more combustible. Summers become longer, which extends the fire season and gives fire-prone lands more chances to burn. Expanding development also puts more people in fire zones. Human activity starts four out of five fires, which increases burned areas sevenfold. Drought across the West, intensified by development and agricultural water use, makes fires more likely. But one of the strongest contributors to fires are fires themselves. Wildfires, it turns out, can make their own weather—which causes them to spread. Two of California’s biggest fires last year produced devastating firestorms. Towering flames heat the air, creating a rapidly rising updraft, which pulls air into the base of the fire, feeding it with oxygen and increasing the intensity. These updrafts may eventually spiral into what’s called a fire whirl—essentially a tornado of flames, with winds up to 150 miles an hour. Meanwhile, smoke fills the air with particulates, on which water vapor can condense, forming thunderheads above fires that can produce lightning and start more fires. Scientists are now studying fire weather, and re-creating it in lab conditions, to better understand how to control wildfires once they begin.

    2 min

  5. 6H AGO

    Wildfires

    In 2018, wildfires burned an unusually high 8.5 million acres. Conversely, 2017 was a very wet year—but that was part of the problem. Heavy rain brings more foliage, which the next year becomes fuel. Wet years are often followed by high-fire years. Wildfires are a natural process, and in many ways can be beneficial: they clear out dead plant matter, control insects and plant disease, return nutrients to the soil, and make way for new growth. It’s even thought that, in the geologic past, fires regulated Earth’s oxygen levels, to keep them in an optimum range for life. But fires are also dangerous to humans and our property. So what to do about that? Forest management helps. Clearing forests and especially slopes of deadwood helps keep fires from spreading. Allowing them to burn is controversial but reduces fuel buildup. Better fireproofing helps, too. Some embers from wildfires are very tiny—small enough to slip between roof tiles and ignite underlying wood. New codes in fire-prone areas call for fire-resistant roof decking. Perhaps most important, we can better monitor ourselves. A new study found that 84 percent of wildfires are set by humans. Accidentally, through downed power lines or untended campfires. Or intentionally, through arson. It may sound obvious, but to avoid becoming victims of fires, we need to become better at not setting them.

    2 min

  6. 6H AGO

    (Almost) A Watershed Event

    From an earlier EarthDate, you may remember John Wesley Powell, who mapped the Grand Canyon and became one of America’s leading geologists. After his trip, he studied the American West—then called the Great American Desert. Powell realized its dryness—with rainfall below 20 inches a year—made it fundamentally different than the rest of the country. He predicted that farming and settlement methods used in the East and Midwest would fail, and proposed to Congress a much different approach: Don’t divide the West into states with straight-line borders as elsewhere; instead, follow the water. Organize it into commonwealths by watershed, so that all water in one area was under one jurisdiction. His proposed map looked very different, with organically shaped borders following ridgelines and drainage plains, each unit containing its own rivers and streams as water sources. Within those watersheds, he proposed a much larger farm size, and reserved drier areas for grazing or no development at all. Powell’s goal was to avoid water battles in the West and better manage resources. But others had different ideas, and Congress was not persuaded. Instead, the government embarked on 100 years of building canals, reservoirs, and irrigation systems. These were successful in populating the West much more densely than Powell proposed. But that population now struggles with water supply, drought, and falling water tables, just as he predicted.

    2 min

  7. 6H AGO

    Magnetoreception

    Many animals have a sixth sense that we humans do not. It’s called magnetoreception, and it allows them to read Earth’s magnetic field to navigate. The magnetic field comes out of the ground at the South Magnetic Pole, flows parallel to the surface across the equator, then dives back into the ground at the North Magnetic Pole. Many bacteria, earthworms, and blind mole rats can sense the direction of this magnetic field and orient to it. We call this compass sense. Migrating animals like butterflies, salmon, sea turtles, and many birds have a more advanced version called signpost sense. They read the direction and inclination of the magnetic field and create mental maps of local anomalies, or “signposts” within it, to chart their paths in three dimensions over great distances. Scientists who study magnetoreception have found that some bacteria have particles of magnetite that align north–south. Some birds have proteins in their eyes sensitive to magnetic fields. But for the more complex signpost sense, animals must have multiple magnetic receptors sending diverse signals that converge in the brain. And we still don’t know what those are or how they work. One reason we may not understand magnetoreception is that we simply don’t know what it feels like, so we’re not quite sure how to study it. We’ll look at other “sixth senses” of the animal kingdom in future episodes.

    2 min

  8. 6H AGO

    Spindletop

    If you’re listening to this while driving, that’s due in large part to the oil boom—which happened over a hundred years ago. At that time, Pennsylvania was the biggest oil producer, and automobiles were scarce. Then, Pattillo Higgins, a self-taught geologist from Texas, had an idea. A low, flat hill outside his hometown was known for black tar that oozed from it. He thought the mound was a salt dome—a rising column of salt—and that oil must have migrated from deeper formations, up its sides. Formally trained geologists chuckled, but Higgins raised enough money to start drilling. After a few dry holes, he was tapped out. Undeterred, he brought in more investors, eventually shrinking his own share to zero—but he kept drilling. In January 1901, his Spindletop well finally struck oil—and did it ever! The reservoir was under such pressure that it shot a geyser of oil 150 ft into the air. For 9 days, workers struggled under a rain of a million barrels of oil, till they were finally able to cap it. The first six Spindletop wells produced more oil than the rest of the world’s wells combined to that point in time. The Texas oil boom had begun. Supply soared and price plummeted. Gasoline became cheap and readily available, helping launch the automobile age and personal mobility like the world had never known—that all of us in our cars still benefit from today.

    20 sec
See All (114)

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
    114
  • Rating
    Clean
  • Copyright
    © Copyright 2026 EarthDate
  • Show Website
    EarthDate