Planet X
Ever since the discovery of the ninth planet, Pluto, astronomers have speculated about whether a still more distant, tenth planet may exist. This thinking was initially based on two lines of ...
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Planet X
Is there another planet beyond Pluto? Prior to 1781 that question could have been asked in regard to Saturn. In that year, Sir William Herschel discovered Uranus, after detecting what he beli...
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Planet X
Planet X