EarthDate

It’s going to be a very noisy summer! This year, more cicadas will fill the air with—song?—than any summer since 1803. Cicadas evolved 150 million years ago, and 3,000 species now live on nearly every continent. These are called “annual” cicadas. They live a few years underground, then crawl up a tree and shed their crusty “underground” skin for a final molt into their winged adult form.  They liv...

If you were to design the perfect industrial material, what would it be like? You’d want it to be strong and lightweight. Easy to form into different shapes. You’d like it to be resistant to corrosion. And to heat. Ideally, you could easily combine it with other materials for more uses. And re-uses. It would be best if all these qualities came in something cheap and abundant. And in fact, they do....

Leonardo da Vinci was one of our most brilliant thinkers. He’s known as an inventor, scientist, mathematician, architect, sculptor and, of course, painter of the most famous portrait in the world, the Mona Lisa. But unless you’re also a painter, you probably haven’t heard of Leonardo’s Rule of Trees. Intent to paint them realistically, he carefully analyzed trees and recognized a pattern, which he...

In 1933, Hungarian explorer László Almásy set out across the Sahara in search of a legendary lost city. What he discovered was far more magical and, at first, completely unbelievable. In a remote ravine, Almásy found a shallow cave. Inside he saw cave paintings of human figures with outstretched arms and legs. They appeared to be flying. But no, Almásy realized, they were swimming—in the Sahara! O...

What if Earth didn’t have a moon? Well, nearly everything about our home planet would be different—so much, we’d hardly recognize it. Our Moon is a quarter the size of Earth, far bigger than most planets’ moons. Scientists think it formed when a smaller planet crashed into Earth 4 billion years ago, knocking off a chunk that eventually became our Moon. Its large size is key to its dramatic effects...

Millions of miles from Earth, the fastest object that humans have ever built is circling the Sun at 430,000 miles per hour, and nearer than any spacecraft has ever dared go. It’s the Parker space probe, and NASA sent it there in 2018 with a mission: to study solar activity. That’s because, in 2024, the Sun is predicted to reach its next solar maximum. It happens when the Sun’s poles flip and its m...

The stegosaurus is known for its unusual features: rows of large, bony plates along its back, spikes on its tail and a cranium so small that early paleontologists thought there must be another brain hidden elsewhere, like in a nerve bundle at the base of the dinosaur’s powerful tail. But it was the purpose of those plates that really baffled scientists—a mystery they’ve been trying to solve for mo...

“Campi Flegrei” in Italian means “fiery fields.” That may not sound like a place you’d want to live, but 360,000 Italians do. Italy is the only country in Europe with active volcanoes on land. The “fiery fields,” just west of Naples, are actually a caldera—the depression left when a volcano erupts and collapses. At the center of the caldera is the Pozzuoli Bay. The coast around it has been densely...

Almost 400 million years ago, our ancestors slowly emerged from the sea to breathe air and populate the land. It may surprise you to know there’s another species making that same transition right now. It’s the mudskipper, a 4- to 12-inch fish that looks like a frog with only front legs. It has a large frog-like head and smooth, green and brown skin dappled with spots. The mudskipper lives in tropi...

In the 1960s, during the Cold War, the U.S. built an Arctic research center in Greenland and called it Camp Century. Except it was actually a secret military operation—code name: Project Iceworm. It was intended to drill a network of nuclear missile launch silos in the Greenland Ice Sheet, designed to survive a Russian ‘first strike.’ The first people there were researchers, to test the ice for su...

When we think of pollination, we usually think of bees, bats or other flying foragers. They visit male flowers to collect nectar and get covered in sticky pollen, which they carry to female flowers, in search for more nectar. Marine plants also reproduce with pollen, but scientists thought water movement carried it from one plant to another. Then researchers discovered what they called “the bees o...

A total eclipse of the Sun is a special occurrence. The last time that the Sun and Moon lined up perfectly for a total eclipse traversing the U.S. was in 2017; another one is due on April 8, 2024, crossing the country from Texas to Maine. While millions of Americans gaze at the sky in wonder, scientists will be hard at work. Because a total eclipse—by blocking the Sun itself—gives us the rare chan...

The most important number in the universe is arguably … pi. Why? Because it defines circles, spheres and wave motion from atomic to galactic scales. Pi is the ratio of a circle’s diameter to its circumference. If the diameter is 1, the circumference is pi. And pi, you may remember, is 3.1415926535 … etcetera, going on forever and never repeating. It was first recognized 4,000 years ago, and since...

We often hear that sea level is rising, but less often that cities are sinking—which may put them in more jeopardy. This may be caused by land rebounding from the last ice age, when it was covered by ice sheets. While some areas spring upward, others that were pushed upward around the periphery of ice sheets are slowly sinking. Or, Earth's surface may rise or fall when a fault slips, or tectonic p...

Remember the movie Jurassic Park? Or every time you’ve seen a reconstruction of a T. rex in a museum? Probably the image that sticks with you is the exposed daggers of fearsome teeth. Well, some Canadian grad students may have proven that image wrong. They discovered something rather elemental: T. rex teeth have very thin enamel. Even thinner than the enamel on mammal teeth. But early paleontologi...

In China, sinkholes are called “heavenly pits.” And China has the largest one in the world, named Xiaozhai. It’s two thousand feet deep and just as wide. Sinkholes occur where Earth’s surface collapses into an underground void. It could be sudden, when a giant hole opens in the ground. Or sinkholes can form slowly, making depressions in the landscape that appear as rolling hills and troughs. Both...

Mountains can shape not only a region’s weather, but its climate. When wind blows warm moist air against a mountain range, the air is pushed upward by the mountain. As it rises, it cools. The moisture within it condenses into rain, which falls on the front side of the range, creating a lush landscape. But behind the range, the air—now empty of moisture—can leave the landscape extremely dry. The mo...

You may remember the Concorde, the passenger jet that rocketed from New York to London in just three hours. And you may wonder, why do we now settle for much slower airplanes? Speed is actually the reason. Achieving it required a great deal of maintenance and fuel, making the Concorde very expensive to operate. But a bigger reason was noise. The Concorde flew at twice the speed of sound, so it cre...

Nearly everything in the universe was made by stars. Stars are fueled by nuclear fusion. They fuse atoms of the lightest element, with only one proton—hydrogen—into the next lightest element, with two protons—helium. In every fusion reaction, they’re creating an atom of a new element. When they’ve used up their hydrogen, they begin to fuse the remaining helium into a heavier element, carbon. Then...

Nematodes aren’t toads at all, but worms. Roundworms, specifically, with cylindrical bodies. Different species are so nondescript we have a hard time telling them apart. That may make them sound uninteresting, but I assure you, they’re anything but. Nematodes are some of the oldest animal lifeforms on Earth, having appeared perhaps a billion years ago. And they’ve been a huge success. To start, th...

What do India and Antarctica have in common? They were once part of the same landmass. Long ago, like all land on Earth, India was contained within the supercontinent of Pangaea. But around 200 million years ago, Pangaea began to break apart. The southern portion separated into Gondwana, which included India. India then began to set its own course. It rifted away from Africa, then tore off from An...

Two of the most powerful forces on Earth are glaciers and volcanoes. What happens when they collide? One dampens the other. And one makes the other more dangerous. During the most recent ice age, glaciers covered a third of Earth’s surface. During this time, volcanic activity declined … Because the sheer weight of ice pressing down on the land increased the pressure on Earth’s mantle beneath the c...

The best thing about mistletoe, you may have thought, is that you can get a holiday kiss under it. But mistletoe is vital to the ecosystems it lives in. Mistletoes are surprisingly diverse. There are over 1,000 species living on every continent but Antarctica and in every environment, from forest to desert. They’re all parasites that grow on grasses, ferns and, most famously, trees. They attach wi...

When the human mind evolved, it only had to process small numbers, like the number of fingers on a hand. To this day, we base our counting systems on that and use it to grasp very large numbers—with limited success. So, when scientists needed to make sense of Earth’s 5 billion–year history, they tied it to something concrete: Earth itself. We started by realizing that Earth’s history is preserved...

Something’s happening high in the mountains, invisible to humans—that can dramatically affect our water supply. It’s a process called sublimation, where a substance goes from its solid form directly to a gas, skipping the liquid state altogether. And water is one of the few substances on Earth that can do this. It takes 80 calories of energy to melt a gram of ice into liquid water. Then another 54...