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NOVA

自然 · 历史
S44 E23 Killer Volcanoes
本集简介

Follow a team of volcano sleuths as they embark on a worldwide hunt for an elusive volcanic mega-eruption that plunged medieval Earth into a deep freeze. The mystery begins when archaeologists find a hastily dug mass grave of 4,000 men, women, and children in London. At first, they assume it's a plague pit from the Black Death, but when they date the bones, they turn out to be too old by a century. So what killed off these families? The chronicles of that time describe a run of wild weather that devastated crops and spread famine across Europe. NOVA's expert team looks for the signature of a volcanic eruption big enough to have blasted a huge cloud of ash and sulfuric acid into the atmosphere, which chilled the entire planet. From Greenland to Antarctica, the team finds telltale "fingerprints" in ice and soil layers until, finally, they narrow down the culprit to a smoldering crater on a remote Indonesian island. Nearly 750 years ago, this volcano's colossal explosion shot a million tons of rock and ash every second into the atmosphere. Across the globe, it turned summer into winter. What would happen if another such cataclysm struck again today?

上一集
2017/10/18 S44 E22 8.3
Secrets of the Forbidden City

Discover the ingenious engineering of Beijing's Forbidden City, the power center of imperial China for nearly 500 years. Discover how the architectural design of this vast complex of palaces and temples enabled it to survive centuries of earthquake shocks. The Forbidden City is the world's biggest and most extravagant palace complex ever built. For five centuries, it was the power center of imperial China and survived wars, revolution, fires, and earthquakes. How did the Ming Emperor's workforce construct its sprawling array of nearly 1,000 buildings and dozens of temples in a little over a decade? How were stupendous 250-ton marble blocks moved across many miles to reach the site? And how did fantastically intricate woodwork, all fastened without nails or glue, enable the palaces to survive hundreds of earthquakes, including recent ones that obliterated nearby modern structures? To find answers, NOVA joins a team of master craftsmen who build a scale model of a typical palace in a seismic lab, then subject it to simulated earthquakes to shake out the secrets of how the Forbidden City has withstood centuries of violent tremors. The Forbidden City is the world's biggest and most extravagant palace complex ever built. For five centuries, it was the power center of imperial China and survived wars, revolution, fires, and earthquakes. How did the Ming Emperor's workforce construct its sprawling array of nearly 1,000 buildings and dozens of temples in a little over a decade? How were stupendous 250-ton marble blocks moved across many miles to reach the site? And how did fantastically intricate woodwork, all fastened without nails or glue, enable the palaces to survive hundreds of earthquakes, including recent ones that obliterated nearby modern structures? To find answers, NOVA joins a team of master craftsmen who build a scale model of a typical palace in a seismic lab, then subject it to simulated earthquakes to shake out the secrets of how the Forbidden City has withstood centuries of violent tremors.