Composition
It has been hypothesized that main-belt comets may have been the source of Earth's water, since the deuterium-hydrogen ratio of the Earth's oceans is too low for classical comets to have been the principal source.
Read more about this topic: Main-belt Comet
Famous quotes containing the word composition:
“The proposed Constitution ... is, in strictness, neither a national nor a federal constitution; but a composition of both.”
—James Madison (1751–1836)
“The composition of a tragedy requires testicles.”
—Voltaire [François Marie Arouet] (1694–1778)
“Vices enter into the composition of virtues as poisons into the composition of certain medicines. Prudence and common sense mix them together, and make excellent use of them against the misfortunes that attend human life.”
—François, Duc De La Rochefoucauld (1613–1680)