Where Did All The Water Come From?

[Ian King]

Where did the water on the Earth come from.

Im sure I heared once that "ALL" the water on the planet came from Comets. That cant be right can it?

Thats a hell of a lot of Comets!

?!?

[Clanad]

When the earth coalesced out of the primordial gas cloud that surrounded the young sun, hydrogen and oxygen were two of the chemical elements incorporated in the earth. Hydrogen is of course by far the most common element everywhere in the universe: you can't
form a planet without hydrogen. Oxygen is less abundant in the universe, but it is a common element too.  Oxygen and hydrogen are chemically quite reactive, and so they both combined with various other elements to form chemical compounds. One of these compounds is water, and water quickly became an
important part of the earth's surficial layer, along with many other familiar chemicals (silica - a major component of sand, calcium carbonate - what limestone is made of, etc.). A significant amount of earth's water has probably been delivered by comets, especially in the first billion years or so after earth formed. (With partial help from Mad SciNetwork)

[bernardo]

It's also a hill of a lut of time for it to collect in.

[solvitquick]

Oops, crossed wires. Please see Tora Tora Tora's identical question where mine and other posts are. I agree with Clanad except for the comet theory. No need for comets to deliver water to Earth.
SIQ.