The most spectacular sign of a geomagnetic storm can look almost supernatural. Green curtains ripple across the night sky, red light appears hundreds or even thousands of kilometres farther south than normal, and photographs of auroras floo...
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Taste a drop of seawater and the answer seems obvious: the ocean contains salt. The more interesting question is how it got there. There are no gigantic salt deposits steadily dissolving int...
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You may already have yawned simply because you read the word. If not, there is a reasonable chance that a photograph or video of someone opening their mouth in a long yawn would do the job....
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It is one of those questions that sounds almost too simple to deserve a scientific explanation. Look up on a clear afternoon and the sky is blue. Yet that familiar color is the visible resul...
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Few astronomical discoveries have produced a nickname as irresistible as the “diamond planet.” About 41 light-years away in the constellation Cancer, 55 Cancri e is a super-Earth nearly twic...
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Space is a vacuum, so an astronaut cannot simply lift a visor and take a sniff. Yet crews returning from spacewalks have repeatedly described something remarkably close to a smell of space:...
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An old tree can carry the shape of an injury long after the branch that caused it has disappeared. A swollen collar may surround the site of a lost limb. Growth rings can bend around the old...
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Why does beer have bubbles? And how many are there in a glass? Beer has bubbles because it contains dissolved carbon dioxide (CO2). Carbon dioxide is produced during the fermentation of beer...
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Why is lake water fresh? Lake water is generally fresh due to the lack of dissolved mineral salts in it.
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