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:
“... 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)
“... 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)
“It’s a rare parent who can see his or her child clearly and objectively. At a school board meeting I attended . . . the only definition of a gifted child on which everyone in the audience could agree was “mine.””
—Jane Adams (20th century)
“I met Jack Kennedy in November, 1946.... We went out on a double date and it turned out to be a fair evening for me. I seduced a girl who would have been bored by a diamond as big as the Ritz.”
—Norman Mailer (b. 1923)
“Spring is strong and virtuous,
Broad-sowing, cheerful, plenteous,
Quickening underneath the mould
Grains beyond the price of gold.
So deep and large her bounties are,
That one broad, long midsummer day
Shall to the planet overpay
The ravage of a year of war.”
—Ralph Waldo Emerson (1803–1882)