If Mars can come within roughly 55 million kilometers of Earth, why does a spacecraft sent there travel something closer to 480 million kilometers — and spend around seven months doing it? The answer is one of the most important ideas in sp...
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Dog owners become experts in noticing small mysteries. One week the mystery is a dog that seems unable to stop licking its front paws. The next it is the same animal stepping onto the lawn a...
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It often begins so subtly that you wonder whether you imagined it: a tiny flutter under one eye, a faint pulse in the eyelid, then another. A few minutes later you are staring into a mirror,...
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You are walking past a town hall, courthouse, school or government building when something looks slightly wrong: the flag is not at the top of its pole. It is hanging lower, leaving an unmis...
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Dig beneath a forest and the roots are not alone. Wrapped around them, penetrating them and extending far beyond them are microscopic fungal threads called hyphae. Together those threads for...
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Few animals have contributed to modern medicine in a way quite as improbable as the horseshoe crab. It looks prehistoric because, in evolutionary terms, it is. Horseshoe-crab relatives were...
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On the morning of November 14, 1963, sailors south of Iceland saw something that looked at first like a ship on fire. A dark column was rising from the North Atlantic. It was not smoke from...
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High on a mountain in late spring, a patch of snow can suddenly look as though someone spilled watermelon juice across it. The surface turns pale pink, rose red or even crimson, sometimes st...
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Imagine taking the mass of a mountain and compressing it until its boundary is smaller than an atom. There would be no miniature rocky mountain inside, no visible sphere and certainly nothin...
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A solitary desert locust can spend its life trying to avoid other locusts. Put enough of them together, however, and something extraordinary begins to happen. The insects become more active,...
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