All questions
5 questions
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How did life begin?
Somewhere on the young Earth, chemistry became biology. We still don't know how.
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How much will Earth warm if CO₂ doubles?
That more carbon dioxide warms the planet has been known for over a century. Exactly how much is a question that took decades to narrow — and is still not closed.
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When did plate tectonics begin?
Earth is the only known planet with moving plates. Estimates of when they started range over three billion years.
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Why did the Bronze Age civilisations collapse?
Around 1200 BC, a connected world of kingdoms fell within a few decades. Nobody agrees on why.
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Why does Earth's magnetic field flip?
Hundreds of times in its history, magnetic north and south have swapped places. We can't predict when the next flip will come.