{"id":5512,"date":"2023-01-31T22:00:00","date_gmt":"2023-01-31T22:00:00","guid":{"rendered":"https:\/\/modernsciences.org\/staging\/4414\/?p=5512"},"modified":"2023-01-26T09:31:14","modified_gmt":"2023-01-26T09:31:14","slug":"how-has-the-inside-of-the-earth-stayed-as-hot-as-the-suns-surface-for-billions-of-years","status":"publish","type":"post","link":"https:\/\/modernsciences.org\/staging\/4414\/how-has-the-inside-of-the-earth-stayed-as-hot-as-the-suns-surface-for-billions-of-years\/","title":{"rendered":"How has the inside of the Earth stayed as hot as the Sun\u2019s surface for billions of years?"},"content":{"rendered":"\n
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\n The slice you see cut out of the Earth reveals its core, depicted here in bright yellow.\n fhm\/E+ via Getty Images<\/a><\/span>\n <\/figcaption>\n <\/figure>\n\nShichun Huang<\/a>, University of Tennessee<\/a><\/em><\/span>\n\n
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Curious Kids<\/a> is a series for children of all ages. If you have a question you\u2019d like an expert to answer, send it to curiouskidsus@theconversation.com<\/a>.<\/em><\/p>\n\n

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How does the inside of the Earth stay boiling hot for billions of years? Henry, age 11, Somerville, Massachusetts<\/strong><\/p>\n<\/blockquote>\n\n

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Our Earth is structured sort of like an onion \u2013 it\u2019s one layer after another. <\/p>\n\n

Starting from the top down, there\u2019s the crust, which includes the surface you walk on; then farther down, the mantle, mostly solid rock; then even deeper, the outer core, made of liquid iron; and finally, the inner core, made of solid iron, and with a radius that\u2019s 70% the size of the Moon\u2019s. The deeper you dive, the hotter it gets \u2013 parts of the core are as hot as the surface of the Sun.<\/p>\n\n

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\n This illustration depicts the four sections beneath the Earth\u2019s surface.<\/span>\n eliflamra\/iStock via Getty Images Plus<\/a><\/span>\n <\/figcaption>\n <\/figure>\n\n

Journey to the center of the Earth<\/h2>\n\n

As a professor of earth and planetary sciences<\/a>, I study the insides of our world. Just as a doctor can use a technique called sonography<\/a> to make pictures of the structures inside your body with ultrasound waves, scientists use a similar technique to image the Earth\u2019s internal structures. But instead of ultrasound, geoscientists use seismic waves<\/a> \u2013 sound waves produced by earthquakes. <\/p>\n\n

At the Earth\u2019s surface, you see dirt, sand, grass and pavement, of course. Seismic vibrations reveal what\u2019s below that<\/a>: rocks, large and small. This is all part of the crust, which may go down as far as 20 miles (30 kilometers); it floats on top of the layer called the mantle. <\/p>\n\n

The upper part of the mantle typically moves together with the crust. Together, they are called the lithosphere<\/a>, which is about 60 miles (100 kilometers) thick on average, although it can be thicker at some locations. <\/p>\n\n

The lithosphere is divided into several large blocks called plates<\/a>. For example, the Pacific plate is beneath the whole Pacific Ocean, and the North American plate covers most of North America. Plates are kind of like puzzle pieces that fit roughly together and cover the surface of the Earth.<\/p>\n\n

The plates are not static; instead, they move. Sometimes it\u2019s the tiniest fraction of inches over a period of years. Other times, there\u2019s more movement, and it\u2019s more sudden. This sort of movement is what triggers earthquakes and volcanic eruptions. <\/p>\n\n

What\u2019s more, plate movement is a critical, and probably essential, factor driving the evolution of life on Earth, because the moving plates change the environment and force life to adapt to new conditions<\/a>. <\/p>\n\n

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