How Old Is That?
Watch And Learn: Our Favorite Content About Earth's History
How To Date A Planet
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Key Facts In This Video
Earth's outermost layer is constantly renewing itself, making the planet appear "younger." 00:21
The mineral zircon is durable, like quartz, but contains small traces of radioactive uranium. 01:31
Uranium-lead dating of zircon tells us that the Earth is at least 4.4 billion years old. 02:33