EarthDate

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.... more

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FAQs about EarthDate:

How many episodes does EarthDate have?

The podcast currently has 391 episodes available.

EarthDate episodes:

April 02, 2026 Solar Superstorm
In other episodes, we talked about solar storms: electromagnetic radiation that flows from the Sun to Earth. In severe cases, they can disrupt our electricity and communication systems.
One very severe event happened a hundred years ago, in 1921, and lasted for 3 days when a large group of sunspots emitted bursts of plasma called coronal mass ejections.
Traveling a million miles an hour, these can take 1 to 3 days to reach Earth. Once here, their energy can create electrical currents that flow along conductive rocks, often jumping to phone and power lines.
In this 1921 event, electricity spiked to 1000 volts along telegraph wires, causing stations to burst into flames and rendering this communication network useless.
Severe solar storms hit earth about once a century, so we’re due for another one. In a much more interconnected world, what could happen this time?
Satellites could be affected, meaning we may temporarily lose GPS and other communication.
Airline passengers might be exposed to increased radiation, and airplane control systems could be impacted.
Modern infrastructure, internet, and electric grids—far larger than a century ago—could be especially at risk.
There are dozens of solar storms each year, but most are not aimed at Earth, so their energy travels into space. Still, scientists monitor solar activity closely to detect solar storms before they may reach Earth, allowing us time to prepare our systems.
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2min
April 02, 2026 Topping Off Everest
The world’s tallest mountain just had a couple of feet added to it.
Mount Everest sits on the Nepal–Tibet border. In Nepalese, it’s called Sagarmatha, meaning “the head of the sky.” In Tibetan, it’s called Chomolungma, “goddess earth mother.”
It got its English name to honor George Everest, who led the survey to map and measure the peaks of India and Nepal in the mid-1800s.
His team used triangulation to sight from point to point, thousands of times, to work out elevations. In 1856, they determined the height of Everest to be 29,003 feet.
That height stuck for a century, until an English-Nepali team finally climbed the mountain, and the survey increased its height to 29,029.
In 1999, the National Geographic Society used a GPS receiver to measure a slightly higher height of 29,035 feet.
But Nepal rejected this new technology and decided to survey it themselves, combining old and new methods.
In 2017, Nepalese climbers placed their own GPS receiver on the summit, then also triangulated its height using laser-guided telescopes from 12 other mountain tops. And China did the same from the Tibetan side.
Then, in a rare collaboration between the countries, they shared their data to arrive at a higher official height for Sagarmatha/Chomolungma: 29,031.69 feet. And that last foot is a doozy!
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2min
April 02, 2026 Farming the Seas
In another EarthDate, we talked about kelp: 100-foot-tall seaweed that grows near shore.
Asian cultures have farmed kelp and other large seaweeds for centuries. If you’ve had Japanese food, you’ve probably eaten it sliced in seaweed salad, dried to flavor soup, or wrapped around sushi.
Seaweed is nutritious, easy to grow and harvest, and requires no irrigation or fertilizer.
It thrives in cool- and cold-water bays, including those that have become barren from overfishing, mismanagement, or agricultural runoff.
These many qualities have encouraged a new generation of seaweed farmers, often former commercial fisherman. They’re creating new vertical seaweed farms in places like the North Atlantic and the Pacific Northwest.
Farmers attach seaweed spores to ropes, then anchor them to the bottom. As the seaweed grows, it takes in carbon dioxide and recharges the water with oxygen, making it ideal for mollusks.
So farmers also grow oysters, scallops, and mussels with the seaweed. Each acre of vertical farm can produce up to 10 tons of kelp and a quarter million bivalves per year.
Researchers have calculated that farming an area the size of Washington state could produce all the food the worlds’ human population needs.
Of course, few of us would want to eat just kelp and oysters. But vertical ocean farms can employ out-of-work fisherman and revitalize ocean environments, all while producing food—a sustainable aquaculture that’s a win-win all the way around.
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2min
April 01, 2026 Ocean Giants
It might surprise you to hear that there are forests underwater.
In temperate oceans near the shore, kelp grows. It’s technically not a plant, but algae–specifically, a brown macroalgae.
And macro it is. The largest species of kelp can reach 130 feet.
They stretch from the dark ocean floor, where they anchor to rocks. A long stem grows upward to where the kelp can reach light. There, it produces long leaf-life blades that conduct photosynthesis.
The stalk and fronds are held upright by gas-filled buoys that the kelp produces, called pneumatocysts.
Kelp are extraordinary growers, able to leap nearly 2 feet in a single day. As they grow, they take in carbon dioxide, nitrogen, and phosphorus from seawater, de-acidifying it, and they return oxygen, enriching their environment for other lifeforms.
And like terrestrial forests, kelp shelters great biodiversity: fish, shellfish and other invertebrates, and mammals like sea otters and sea lions.
Kelp is often harvested for algin, a gel-like substance used as a thickener in cosmetics, shampoos, toothpastes, and foods like pudding and ice cream.
On top of that, kelp is nutritious, rich in potassium, iron, and other minerals and vitamins. It’s already a staple in many Asian cuisines and is gaining popularity in others.
These qualities make kelp and other large seaweeds ideal candidates for ocean farming, which we’ll talk about in another EarthDate.
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2min
April 01, 2026 Really Odd Duck-bill
We’ve talked about some weird animals on EarthDate, but the platypus may be the strangest.
They’re famous for having a duckbill and a beaver tail. But that’s just the start of it.
Platypuses are monotremes, one of just three mammals—all in Australia—that lay eggs. But they also produce milk to nurse their young once hatched.
And they’re one of the few venomous mammals. Males have sharp spurs on their back legs that can inject poison potent enough to send a human to the hospital.
They spend much of their time underwater at night, making over a thousand short dives in a 24-hour period, hunting worms, crayfish, and water insects.
They close their eyes, ears, and nostrils underwater, so they rely on their bill to navigate. It has two types of electroreceptors, using direct current to avoid large objects when swimming and alternating current to detect the muscle activity of their prey.
They then zero in, using sensitive pressure receptors that can detect tiny movements in the water—less than the thickness of a human hair.
Their hips are splayed like a reptile’s. Their fur fluoresces under UV light like some marsupials. Their eyeballs are wrapped in cartilage like a bird but shaped like those of other water mammals. And their gene code shows ancestry from each of these animal groups!
Of course, all this weirdness is in the eye, or the bill, of the beholder. To a platypus, we furless bipeds may be the truly odd ducks.
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2min
April 01, 2026 The Value of Snowpack
If you live in or visit the mountains, you can look at the snow-covered hills as nature’s water towers. As that snow melts, it could provide 75 percent or more of the area’s freshwater each year.
That’s true far downstream from the mountains too, and even in snowy flat areas. Around the world, snow provides 50 percent of our total annual freshwater supply.
And it does more than that: snow reflects sunlight, keeping areas cooler and making it possible for snow to accumulate.
Snow protects against erosion, slowly melting and deeply recharging the soil with water–preventing it from leaving the area as runoff.
Melting snow gradually fills streams, which slowly fill rivers, providing a steady supply of freshwater that can last through summer.
Warmer winters are disrupting this process though.
So-called ‘dry snow droughts’—as we’ve seen in California’s Sierra Nevada—sometimes with just 5 percent of normal snowfall, have led to water shortages for the region’s growing cities.
Warm snow droughts, where precipitation falls as rain—as we’ve seen in the Pacific Northwest—melt the snowpack early, causing heavy streamflow and even floods in winter and early spring, again depriving communities and agriculture of water later in the year.
So, whether you’re a ski bum or someone who works in the billion-dollar winter recreation industry, a fisherman or a farmer, or just a city dweller who drinks water, we should all hope for cold, snowy winters.
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2min
March 31, 2026 Bite of the Bumblebee
You may have heard that bumblebees shouldn’t be able to fly. That’s a myth actually, as any flying bumblebee will tell you. The science of their flight is now understood.
But the bees hold another mystery that could affect human agriculture.
Bumblebees hibernate over winter, and when they emerge in the spring, they’re hungry.
But what if the plants they rely on for pollen and nectar aren’t yet producing? The bees actually force them to do it.
Like their honeybee cousins, bumblebees scout their environment to identify the best flowers.
Scientists noticed a strange behavior on plants that were not flowering: the bees bit a pattern of tiny holes in the leaves. Soon after, the plants bloomed—up to 1 month earlier than normal.
Once they started flowering, the bees stopped biting them and started harvesting the nectar.
Researchers tried to replicate the bees’ technique by making their own tiny holes in the leaves of different plants. They bloomed earlier too, but only by about a week.
How the bees produced their better results is still a mystery. Perhaps they’re leaving behind a biochemical that accelerates the plants’ chemistry.
If humans can figure out how they do it, it’s possible we could force crops to bloom earlier, extending growing seasons, perhaps adding another growing season in the year, thus increasing annual crop yields.
Leave it to the bumblebee, that impossible flyer, to show us how to bend the laws of nature.
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2min
March 31, 2026 Deepest Dive
In another EarthDate, we talked about Challenger Deep, the deepest point in all the oceans, at almost 7 miles down.
The first humans to explore it were a Swiss oceanographer and U.S. Navy Lieutenant. They built a special deepwater submarine called a bathyscaphe, and in 1960, headed for the bottom.
It took them 3 hours to reach the western pool of Challenger Deep at 35,000 feet. But they stirred up so much sediment, they couldn’t see anything.
That, and a worrisome crack in a window, cut their trip short. After 20 minutes, they jettisoned their ballast and began their 2-hour trip to the surface.
The next visit came 50 years later, when film director James Cameron co-designed his own ultradeep submersible and captained it solo into the deeper Eastern pool, at 35,800 feet.
He spent 2 hours motoring slowly around the bottom, taking photos and video, but didn’t see any creature longer than 1 inch.
Recently, explorer Victor Vescovo piloted his craft slightly deeper than Cameron, now holding the world record. His scientific team then made a few more trips to the bottom, discovering a new species and gathering samples.
They found small crustaceans with high concentrations of chemicals banned in the 1970’s. And, a plastic candy wrapper.
A reminder that, even in places where humans can scarcely visit, our impact can be seen.
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2min
March 31, 2026 The Deepest Deep
Mt. Everest, at just over 29,000 feet above sea level, may be the highest point on Earth’s surface—but what’s the lowest?
Well, the deepest part of the deep sea is the Mariana Trench in the Pacific, off the island of Guam, about halfway between Japan and Australia.
It’s five times as long as the Grand Canyon and more than a mile deeper than Everest is tall.
And the deepest point in the trench is called Challenger Deep, nearly 36,000 feet below sea level. It’s named after the Challenger 1 and 2 exploration ships which, in the 1870’s and 1950’s, first measured Earth’s lowest point using iron weights and very, very long metal wires.
Deep sea trenches like the Mariana form along tectonic plate boundaries, where plates collide and one is forced under the other, pushing down the surface of Earth in what’s called a subduction zone.
No sunlight can reach this deep, so the trench is in absolute darkness. Life and the food web are very sparse, with some creatures relying on chemosynthesis—feeding on methane or sulfur.
The water is near freezing, and water pressure at the bottom of Challenger Deep is 1000 times that at sea level—enough to crush the bones of humans.
Of course, that didn’t stop humans from wanting to explore it. Who they were, how they did it, and what they found, we’ll talk about on another EarthDate.
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2min
March 31, 2026 Beneficial Viral DNA
In earlier episodes, you heard that trillions of viruses live peacefully, even beneficially, within each of us today.
And that our ancestors battled now-extinct “fossil viruses,” which are preserved in our own genetic code.
Turns out, that’s been beneficial too.
For instance, viruses helped drive our evolution.
100 million years ago, proto-mammals were infected with a virus that encoded into their DNA the ability to produce syncytin, a protein that viruses use to fuse cells together so they can move between them.
But these early mammals evolved to use this protein in a different way: to fuse the placenta to the uterus, allowing nutrients to pass from mother to fetus and making live birth possible.
Since humans diverged from apes, our proteins have adapted frequently to viral threats, even if they’re not part of the immune response. In fact, virus interactions now make up a third of all our protein adaptations.
Finally, researchers found that ancient viral DNA in our genetic code prompts a more vigorous response to new viral threats.
In experiments, when they removed fossil virus DNA from a cell, its immunity was severely weakened. Restoring the viral DNA restored the immune response.
While a rare few viruses have been quite harmful to humans, the vast majority—over millions of years—have helped us to become what we are and then to remain healthy.
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2min

FAQs about EarthDate:

How many episodes does EarthDate have?

The podcast currently has 391 episodes available.