『EarthDate』のカバーアート

EarthDate

EarthDate

著者： Switch Energy Alliance
無料で聴く

概要

 EarthDate is a short-format weekly audio program delivering concise, science-based stories about the Earth: its geology, environments, and the processes that shape our planet over deep time and today. Beginning in 2026, EarthDate is managed by Switch Energy Alliance and hosted by SEA's founder Dr. Scott W. Tinker. Together, we explore earth systems, natural resources, and their relevance to everyday life, with a focus on clear, accessible science education for broad audiences. EarthDate is written and directed by Emmy-winning filmmaker Harry Lynch, and researched by Lynn Kistler. We search for captivating stories to remind listeners that science can enlighten, educate and entertain.Copyright 2026 EarthDate 地球科学 生物科学 科学
エピソード
  • How 10 Fingers Became 12 Hours

    How 10 Fingers Became 12 Hours
    2026/03/28
    We have 10 fingers, so we’ve based our common counting systems on 10. Why then, do we divide the day into 12 hours and the hour into 60 minutes? To understand, we need to go back 3000 years. Babylonians also used their hands to count, but wanting to count higher than 10, they devised a different system. They used their thumb to count the three segments of their four fingers to get 12. They marked that 12 by raising a finger on the other hand. Twelve times five fingers is 60. 2500 years ago, when people started using sundials, it seemed only natural to divide the day in 12. Egyptian astronomers then found 12 stars to mark the passing of time in the night sky, making a 24-hour cycle. Early Greek mathematicians realized they could divide a circle into six equilateral triangles like a sliced pizza. Around 2200 years ago, the first Greek astronomer to describe a round Earth wanted a system to navigate it. He took that 6-part circle and divided each part by 60 to get 360 degrees. Another Greek divided those degrees further, into 60 minute parts, and those into 60 secondary parts. A few centuries later, these geographic minutes and seconds were applied to the 24-hour day. But it would take another thousand years before we could accurately measure that second, which we’ll cover on another EarthDate.
    続きを読む 一部表示
    2 分
  • Wondrous Waterfalls

    Wondrous Waterfalls
    2026/03/28
    The waterfall. In concept, it’s simple: just water… falling. But in life, waterfalls are a wonder. Beautiful, frightening, powerful, calming, deafening, soothing—sometimes all at once. They’ve been inspiring humans for millennia. When water flows over a wide shelf, it’s called a block falls. The widest is Victoria Falls in Zambia, over one mile across. Called “smoke that thunders” in the local language, it can be heard 25 miles away. Human tools have been found there from 50,000 years ago. The tallest falls are in Venezuela. Angel Falls cascade down the face of a half-mile-high rock shelf in a horsetail plume that falls so far, the water turns to mist before it can reach the ground. There, the river reforms to continue its path. Yosemite Falls in California is 200 feet shorter but nearly as spectacular. But by far, the biggest waterfall in the world is “out of sight”: Water falling into water under more than half a mile of ocean. Off the coast of Greenland, a huge torrent of dense, very cold water surges over a shelf into the warmer North Atlantic, plummeting 11,000 feet. Its flow is 30 times that of all the rivers that flow into the Atlantic, an astonishing 1.3 trillion gallons per second! Next time you get out into nature, make it a point to take in a waterfall.
    続きを読む 一部表示
    2 分
  • Under Greenland’s Ice Sheet

    Under Greenland’s Ice Sheet
    2026/03/27
    Greenland is Earth’s largest island, and most of it is covered by ice up to 2 miles thick. Scientists decided to investigate the age of this ice sheet and were surprised to find that not that long ago, there wasn’t one. They used ice cores to date different areas, then flew planes over it with special ice-penetrating radar. The radar identified bands of softer and harder ice and layers within them, which they matched to the ice cores to determine different ages of ice across the island. Turns out Greenland’s ice accumulated in three separate events: the oldest beginning 130,000 years ago; the middle one during the last Ice Age; and the most recent just 12,000 years ago. Equally interesting, the radar revealed the bedrock beneath the ice sheet to find that a giant rift as deep as the Grand Canyon and even longer, at almost 500 miles, splits the island and exits north into the Arctic Sea. It’s possible this was formed by massive floods as much as 2 million years ago. They also found a huge impact crater that appears to have been made by a mile-wide meteorite, which might be the one that caused the lingering Ice Age discussed in a previous episode. It’s unclear when it struck Earth, but it was at least 12,000 years ago, since the young ice above it is undisturbed. This new technology has given us a remarkable first look at Greenland’s landscape, otherwise hidden beneath the ice.
    続きを読む 一部表示
    2 分
まだレビューはありません