How did earth get all this water?

Earth does have a lot of water relative to other planets, and I am curious about that as well. That said, a lot of water on the surface doesn't necessarily = a large percentage of water. Compared to the total volume and mass of the Earth, as I understand it, water is a pretty small portion.

I suspect it has something to do with the temperature of Earth, the thickness and composition of our atmosphere, and our position relative to the sun....

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"Regret can only change the future" -Me

"Every judgment teeters on the brink of error. To claim absolute knowledge is to become monstrous. Knowledge is an unending adventure at the edge of uncertainty." Frank Herbert, Dune 1965

You have a real good question here. I think the standard answer is comets did it but it seems to me a better answer can be found by looking at the atmosphere of Venus as a good example of how the atmosphere of Earth was 4 or 5 billion years ago. Earth must have an atmosphere much like the atmosphere now on Venus. Earth evolved because it has enough mass and is far enough from the sun to capture and hold hydrogen. Venus can't do that trick so water is out of the process on Venus. As you know water is made of hydrogen and oxygen and if hydrogen can excape then water can't exist. This detail is unknown to science at this time as are other very simple facts.

Thanks Jim. So as I understand you the earth "captured" and then retained hydrogen, which over time combined with oxygen to form water. So where did the hydrogen come from?

Emanuel

I don't really know what happened since I wasn't there. So my perspective is just one idea. The comet solution does nothing for me so I keep looking as you seem to do. Anyway, the hydrogen could have been in the mix when the planet formed and cooled in the form of water. Or not. It could have been captured over time from the solar wind which is mostly hydrogen. I never did the math on this detail but it seems like a good as any solution if you need one. Although it might be somewhat like a solution a parent gives when the child asks about the birds and bees. I don't know and can't give you an authorative answer because I'm not well versed in theories about how plants are whipped up out of dust. And don't believe them anyway.

<blockquote id="quote"><font size="2" face="Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote"><i>Originally posted by Jim</i>
<br />You have a real good question here. I think the standard answer is comets did it but it seems to me a better answer can be found by looking at the atmosphere of Venus as a good example of how the atmosphere of Earth was 4 or 5 billion years ago. Earth must have an atmosphere much like the atmosphere now on Venus. Earth evolved because it has enough mass and is far enough from the sun to capture and hold hydrogen. Venus can't do that trick so water is out of the process on Venus. As you know water is made of hydrogen and oxygen and if hydrogen can excape then water can't exist. This detail is unknown to science at this time as are other very simple facts.
<hr height="1" noshade id="quote"></blockquote id="quote"></font id="quote">Water is relatively abundant in the solar system. What is rarer is liquid water because the conditions for its existence and persistence is rare. Many types of asteroids have a considerable percentage of their mass as water in the form of hydrates so the comet/asteroid bombardment theory isn't totally implausible. Of course, it begs the questions where did the asteroids come from and where did they get their water?

JR

Another more plausible solutions lies in two facts that make earth special in the solar system.

Fact 1: The most plentiful anion in minerals is oxygen. It can be released as oxygen gas through volcanic activities, this is common on earth.

Fact 2: Earth is surrounded by a strong magnetic field which prevents the sun from blowing away an atmosphere where escaping volcanic oxygen was able to combine with the original hydrogen atmosphere to create water vapor which then rained down on earth.


Mark Vitrone