If you smoothed out the Earth’s crust, the oceans contain enough water to cover the globe a couple of kilometers deep. So why is there land today? SciShow host Hank Green says that it’s possible that land didn’t always exist and, technically speaking, it doesn’t have to. Tune in as Green explains the science.
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Back in the Middle Ages, miners noticed that the deeper they dug into the Earth, the hotter it got. Physicist William Thompson, aka Lord Kelvin of temperature fame, theorized that Earth started out hot and has been cooling ever since. He used the hypothesis to predict the age of our planet, but overshot the number by several million years. What was missing in his theory, was his failure to detect the rigidity of the Earth’s mantle, the layer between the crust and the core. MinuteEarth host Emily Elert explains further.
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More than 600 million years ago, ice sheets covered our planet on both land and sea, with temperatures dipping to -130 degrees celsius. And there was no escaping the cold at the equator, where temperatures fell below zero!
Amazingly, this happened twice in the Cryogenian Period. So what happened? “The most popular theory is that our planet thermostat just failed,” says PBS Eons narrator Kallie Moore. “That thermostat is the carbon cycle, the flopping back and forth of carbon between the atmosphere and the Earth’s crust, and it starts with volcanoes.” Tune in to learn the details.
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The CIA classified a book on earth’s catastrophe cycle and crust displacement in 1966. With the focus and publicity of the topic at the time, why classify THIS one, wait so long to release it, and so-heavily sanitize the document?
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The doom and gloomers gave the Oil Age an early epitaph in the early 2000s, claiming fossil fuels had run their course and there was no more oil to be pumped on the planet. Fast forward 15 years and there’s oil everywhere. The world pumps 93 million barrels of oil a day and there’s still more than a trillion barrels waiting to be extracted in the Earth’s crust. So will we ever run out of oil? Biologist and science writer Joe Hanson explains in this edition of It’s Okay To Be Smart
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It was a mystery to geologists why our continents drifted about the planet, occasionally glomming together then breaking apart. Not until the 1960s was it discovered that the Earth’s crust is broken down into fragments called tectonic plates–and they are moving. Host Henry Reich explains the fundamentals of this phenomenon in this edition of MinuteEarth.
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It seems we’ve read or researched just about everything there is to know about our little blue planet. But Danger Dolan is betting there are at least 15 facts that will tickle your innards, such as the twin planet named Theia that crashed into Earth 4.5 billion years ago. The planet, about the size of Mars, was eventually absorbed into Earth’s crust. Check 14 more fascinating facts about our home.
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Six-hundred million years ago Earth was basically composed of three huge landmasses and a lot of water. Then the planet evolved into seven continents as the Earth’s crustal plates shifted and collided over long periods of time. In this edition of SpaceRip, see what Planet Earth will look like in 100 million years.
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