Definition of A Double Planet
There has been some debate in the past on precisely where to draw the line between a double-planet and a planet–moon system. In most cases, this is not an issue because the satellite has a small mass relative to its host planet. In particular, with the exception of the Earth–Moon and Pluto–Charon systems, all satellites in the Solar System have masses less than 0.00025 (1⁄4000) the mass of the host planet or dwarf planet. On the other hand, the Moon to Earth mass ratio is 0.01230 (≈ 1⁄81), while the Charon to Pluto mass ratio is 0.117 (≈ 1⁄9).
Read more about this topic: Double Planet
Famous quotes containing the words definition of a, definition of, definition, double and/or planet:
“Definition of a classic: a book everyone is assumed to have read and often thinks they have.”
—Alan Bennett (b. 1934)
“... we all know the wag’s definition of a philanthropist: a man whose charity increases directly as the square of the distance.”
—George Eliot [Mary Ann (or Marian)
“One definition of man is “an intelligence served by organs.””
—Ralph Waldo Emerson (1803–1882)
“You spotted snakes with double tongue,
Thorny hedgehogs, be not seen.
Newts and blindworms, do no wrong,
Come not near our Fairy Queen.”
—William Shakespeare (1564–1616)
“...I, his wife, rested and was warmed in the sunlight of his loyal love, and glorious fame, and now, even though his beautiful life has gone out, it is as when some far off planet disappears from the heavens, the light of his great fame still falls upon and warms me.”
—Julia Dent Grant (1825–1902)