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  • California’s Sinking Valley

    California’s Sinking Valley
    Feb 24 2026
    California’s Central Valley is an agricultural bonanza, producing a third of America’s food crops. But it’s facing serious water challenges. The valley floor is 20,000 sq miles of some of the most fertile soil on Earth. Here, the sun shines 300 days a year. More than 250 different crops grow, worth $17 billion per year. The valley was developed into farmland around the turn of the twentieth century. When farmers arrived, they began to drill wells into the fresh-water aquifers below. By the 1930s, scientists began to notice an impact. Some of the aquifers, with their water levels and pressure drawn down, compacted. This meant they would never refill to earlier levels, and the land above them subsided. This continued into the 1970s, when sinking land, up to 30 ft in parts of the valley, had damaged roads, bridges, and buildings so dramatically that California spent millions to repair them and built canals to bring in water. The problem was alleviated—until conservation elsewhere in the state reduced water in the canals and valley farmers pulled hard on their wells again. The wells remained unregulated until 2012, when California passed serious water legislation. It will be decades before it’s fully phased in, but the hardest-hit areas are being addressed now. In the meantime, the valley floor and the water table continue to fall.
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    2 Min.
  • Stories Hidden in Pollen

    Stories Hidden in Pollen
    Feb 24 2026
    Grains of pollen are like Mother Nature’s fingerprints, allowing scientists to track the migratory paths of dinosaurs and solve long-cold murder cases. Flowering plants evolved 100 million years ago, and within 30 million years dominated the planet. Today, there are almost 400,000 species. One reason for their global success is their remarkable fertilization system. A single flower can produce hundreds of thousands of pollen grains, which can be distributed by the wind, insects, or animals, fertilizing other plants miles away. Each plant produces a distinct-looking pollen grain. And each place on Earth, even each square block or backyard garden, has a distinct mix of plants. By studying the mix of pollen grains found on a person, animal, or object, scientists can now tell precisely where they have been. And since pollen is highly durable, outlasting the plants that produced it by thousands of years and surviving in the fossil record for millions, scientists can use it for ancient detective work. Recently, paleontologists used fossil pollen in the digestive tracts of dinosaurs to tell what they ate and where. Forensic palynologists now use pollen found on murder victims and suspects to place them in the same location, or even to discover where bodies have been hidden. The new science of palynology is cross-pollinating many other fields, allowing a deeper understanding of Earth.
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    2 Min.
  • Melting Permafrost

    Melting Permafrost
    Feb 24 2026
    Since 2000, the Arctic has warmed more than other areas, up to 5°F. And that’s beginning to melt the permafrost. In the Arctic winter, the earth is frozen, from tens to thousands of feet down. In summer, the top several feet melt, creating a so-called active layer where plants can take root. Below that is permafrost: frozen soil that contains a great deal of ice. For these regions, it’s like bedrock—stabilizing the active layer and providing a solid footing for buildings. But as the melting reaches deeper into the ground, the permafrost is not so permanent and is becoming unstable. Roads in Alaska and Canada are beginning to undulate and ripple, and runways are at risk. Foundations are shifting, making some buildings and houses unusable. Surface water drains and floods unpredictably. What widespread effects could this have? Permafrost, like regular soil, contains organic material from dead plants and animals. As it melts, the organic matter decays, releasing CO2 and methane, both greenhouse gases. This could create a feedback loop of continued greenhouse gas release and further warming. But melting permafrost is also creating a deeper soil layer, which may allow forests to replace tundra. In other places, it’s toppling existing forests and replacing them with wetlands. These would absorb CO2. With permafrost covering nearly a quarter of the Northern Hemisphere, scientists are keeping a close eye on these changes and how they impact climate models.
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    2 Min.
  • The Colorful History of Paint

    The Colorful History of Paint
    Feb 24 2026
    Humans have been painting to memorialize their lives since the Stone Age, using techniques that endure to this day. The earliest art supplies we’ve found—abalone shells full of ground ochre and charcoal—were in the Blombos Cave in South Africa, and are up to 100,000 years old. But we haven’t yet found paintings to go with them. By 40,000 years ago, tribes in Europe, Australia, and Indonesia painted images of hunters and herders on cave walls, and had expanded their palette to include many colors. Pigments for these paints included blood, sap, berry juices, dried plants and roots, and many minerals. Iron oxide pigments were highly valued for their durability, and prehistoric mining trails around the famous Lascaux Cave in France suggest that, 25,000 years ago, painters traveled many miles for these materials. Early artists mixed their pigments into paint using water, saliva, urine, or animal fats. They then applied them with fingers, brushes, or by blowing them through hollow bones, like today’s airbrushes. The Egyptians continued the modern advancements, mixing paints with binding agents like egg and began painting on plaster. Greeks and Romans expanded upon these techniques, to create a painting style not matched till the Renaissance—when Italian artists made paint with plant oils to create works of astonishing color and depth that still captivate viewers today.
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    2 Min.
  • How Old Is Earth?

    How Old Is Earth?
    Feb 24 2026
    Humans have wondered about the age of Earth for centuries. In the 1600s, a bishop worked backwards through generations of “begats” in the Bible to come to a very specific date for Creation: October 26, 4004 BC. At 6 PM. In the 1700s, scientists developed their own theories. Recognizing that different layers of rock represent different periods in Earth history, they calculated a much looser estimate: 1 million to 1.6 billion years old. By the early 1900s, scientists began to understand radioactivity, and found that each radioactive element has a half-life—a specific amount of time it takes to lose half its energy. They could use these half-lives to more precisely date Earth’s rock layers, pushing the age of the oldest ones to 3 billion years. With improved dating techniques, we now find rocks between 3.5 and 4 billion years old on every continent. But there are limits to this method. The surface of Earth is always eroding and renewing itself, and old Earth rocks tend to get recycled. To reach back further in time, we needed a place of the same age, but undisturbed by plate tectonics, like the moon. The oldest rocks we’ve found there date to around 4 and a half billion years. By studying these, and meteorites that landed on Earth from within our solar system, we’ve arrived at an age for Earth of 4.55 billion years.
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    2 Min.
  • The First Americans

    The First Americans
    Feb 24 2026
    You probably learned in school that the first Americans came from Siberia, crossing the Bering Strait into Alaska. That ancient history is still widely accepted—but it has a few new wrinkles. Archaeological records now show that humans left Siberia 25,000 years ago but didn’t arrive in North America till 15,000 years ago. Where were they for 10,000 years in between? New research suggests they were living in the Bering Strait, in a now-submerged land called Beringia. During the peak of the last Ice Age, much of Earth’s water was held in continental ice sheets that caused ocean levels to drop 400 ft. The land of Beringia was exposed, as much as 3 million square kilometers. It appears humans were trapped in this inhospitable terrain by glaciers to the east and west. This great frozen tundra would not have supported the bison and mammoth that other early humans depended on. But it could have sustained caribou. Perhaps more important, it held arctic oases of trees and brush, enough to provide shelter and firewood for the Beringians, who survived 10,000 years of winter by burning wood and animal bones. They stayed in Beringia long enough to become genetically distinct from their Siberian ancestors, which we see in DNA analysis of Native tribes in both North and South America— the majority of whom descended from the Beringians. It’s a remarkable testament to human resilience.
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    2 Min.
  • El Niño

    El Niño
    Feb 24 2026
    Strange weather around the world is often blamed on El Niño. Who is this “boy,” and how does he cause so much trouble? El Niño is simply warmer-than-normal water in the Pacific, off South America. It was first noticed by sailors in the 1600s, who named it after the Christ Child since it came in December. We now know that El Niño lasts several months to several years, returns every 2 to 7 years, and is caused by atmospheric pressure. In a normal year, high pressure over the Pacific and low pressure over Australia and Indonesia form trade winds. These blow west across the Pacific, pushing warm surface water with them—which brings humidity and rain to Australia. Meanwhile, cold water from the deep replaces the exiting warm water, replenishing nutrients and fish stocks along South America. But in an El Niño year, the high- and low-pressure areas are reversed, and trade winds stop. Warm water stays put. Australia and Indonesia get less rain. South America gets it instead. The shifting temperature patterns alter the jet stream, which changes the tracks of seasonal rains. This makes it warmer and drier in the northern U.S. and Canada. Colder and wetter in the southern U.S. And causes droughts as far away as India. La Niña is a natural compensation—colder-than-normal water in the western Pacific—which sometimes follows El Niño and brings opposite weather effects.
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    2 Min.
  • World’s Oldest Water

    World’s Oldest Water
    Feb 24 2026
    In one of the world’s deepest mines, scientists have discovered some of the world’s oldest water. In northern Canada, the Kidd Creek Mine is almost 10,000 ft deep. Here, miners search for copper, zinc, and silver ore in volcanic material that was once the floor of an ancient sea. At the very bottom of the mine, they drilled an exploratory borehole even farther down to look for more metal ore. What they found was possibly the oldest water in the world, trapped in the rocks for more than 2 billion years. Why is this important? It provides a snapshot of Earth from that far distant time before there was anything but single-celled life on the planet. And what was water like then? Very different. The water from this ancient sea is eight times saltier than today’s ocean water. Trapped in it are helium, argon, neon, krypton, and xenon gases. And, surprisingly, sulfur isotopes which show that ancient single-celled organisms must have lived in it long ago. Scientists are still analyzing this ancient water, in hopes of better understanding not only our juvenile Earth, but also the types of extreme environments we may find elsewhere, like on the moons of Saturn and Jupiter, where there are vast oceans of water trapped beneath ice sheets. If basic life forms existed in our ancient water, without sunlight or any contact with the surface, it is possible we will find them in other places, too.
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    2 Min.