Look up on a clear night and the most obvious feature of the universe is not the stars. It is the darkness between them. That darkness seems perfectly ordinary, yet for centuries it posed a surprisingly deep problem. If space contains an en...
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A dog stops halfway through a walk, lowers its head and begins grazing with the concentration of a miniature cow. For many owners, what happens next seems obvious: the dog must have an upset...
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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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Near the heart of the Milky Way lies a cloud with a reputation that sounds invented for a science-fiction cocktail menu. Sagittarius B2 contains alcohol. It also contains ethyl formate, an o...
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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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Imagine putting the entire Solar System on a cosmic scale: the eight planets, every known moon, the asteroids, comets, dwarf planets, dust and the enormous Sun. The result would be absurdly...
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At this moment, Earth is moving in several different ways at once. It spins on its axis, circles the Sun at roughly 30 kilometers per second, and accompanies the entire Solar System on a vas...
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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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In the Chihuahuan Desert of northern Mexico, where Durango, Chihuahua and Coahuila approach one another across an immense dry basin, a patch of landscape has acquired one of the strangest re...
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For generations, chemistry books could place bismuth near the end of the periodic table's stable territory. Its naturally occurring isotope, bismuth-209, showed no detectable radioactive dec...
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