Darkness at Night: A Riddle of the Universe

  title={Darkness at Night: A Riddle of the Universe},
  author={E. Harrison and P. H. Andersen},
  journal={Physics Today},
Why is the sky dark at night?The answer to this ancient and celebrated riddle, says Edward Harrison, seems relatively simple: the sun has set and is now shining on the other side of the earth. But suppose we were space travelers and far from any star. Out in the depths of space the heavens would be dark, even darker than the sky seen from the earth on cloudless and moonless nights. For more than four centuries, astronomers and other investigators have pondered the enigma of a dark sky and… Expand
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