Project Gutenberg #20417
The Outline of Science, Volume 1
J. Arthur Thomson
1922Thomson's broad popular-science survey of astronomy, biology, and Earth science, prepared section by section from Project Gutenberg HTML.
Project Gutenberg #20417 Public domain in the United States Cover source Local typographic cover created for MojiMori from public-domain source metadata
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We may conclude our survey of the solar system with a word about "shooting stars," or meteors, and comets. There are few now who do not know that the streak of fire which suddenly lights the sky overhead at night means that a piece of stone or iron has entered our atmosphere from outer space, and has been burned up by friction. It was travelling at, perhaps, twenty or thirty miles a second. At seventy or eighty miles above our heads it began to glow, as at that height the air is thick enough to offer serious friction and raise it to a white heat. By the time the meteor reached about twenty miles or so from the earth's surface it was entirely dissipated, as a rule in fiery vapour.