Thread: How much of Earth's mass is water by weight percentage?

1. How much of Earth's mass is water by weight percentage?

How many percents of Earth's mass are water? I seem to remember some 3 percents, but I don't know. And how much more would it have to be to submerge all the continents including Mount Everest in the ocean? How much more would it have to be to have high pressure ice at the bottom like the hypothetised super-deep ocean planets that form beyond the ice line?

2. Originally Posted by m1omg
How many percents of Earth's mass are water? I seem to remember some 3 percents, but I don't know. And how much more would it have to be to submerge all the continents including Mount Everest in the ocean? How much more would it have to be to have high pressure ice at the bottom like the hypothetised super-deep ocean planets that form beyond the ice line?

mass of Earth = 5.9742 × 10^24 kilograms
mass of Oceans = 1.384 × 10^21 kg (Modified from Clark, W. C. (ed.). 1982. Carbon Dioxide Review: 1982, p. 469, Oxford University Press, New York - http://hypertextbook.com/facts/1998/AvijeetDut.shtml )
provided those numbers are accurate and my sans coffee morning number juggling is correct, it looks like the oceans have somewhere around 2 one hundredths of a single percent of the mass of the Earth. Which actually seems about right as they are just a thin film on the surface of the planet. As to the rest, I'll leave that for others, or at the least, until after I've made and drank some coffee.

3. There is also water in the atmosphere, water in ice and snow packs, ground water and aquifers, and water chemically bound in rocks. I have no data, but I suspect that would not even add another order of magnitude, so we are still talking well under 1%.

P.S. - Just saw Grant's post - didn't realize mantle rock was that wet. But we are still around a couple of percent.

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I'd guess that the ocean/air contribution is overwhelmed by the water content of the solid Earth. The water content of upper mantle rock is about 0.1% by weight, for instance. Since the mantle makes up more than half the Earth's mass, it seems likely that mantle water outweighs ocean water, though I can't see how it could get anywhere close to 3% of the Earth's mass.

Grant Hutchison

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Has any of this been confirmed, that there may be x10-30 the water of all the oceans, inside the earth?
http://news.nationalgeographic.com/n...aterworld.html
http://ldolphin.org/deepwaters.html

"We know more about the far side of Pluto than what goes on 4000 miles under our feet" (Arthur C Clarke)

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Originally Posted by wd40
Has any of this been confirmed, that there may be x10-30 the water of all the oceans, inside the earth?
Extrapolating my 0.1% to the entire mantle gives that order of magnitude.

Originally Posted by wd40
Ah, there's the likely source of m1omg's 3%: an estimate of the Earth's water budget at the end of cometary bombardment. So probably best thought of as "theoretical water, at present unobserved" rather than a confirmed component of the present-day Earth.

Originally Posted by wd40
"We know more about the far side of Pluto than what goes on 4000 miles under our feet" (Arthur C Clarke)
Arthur C Clarke used the phrase "far side of Pluto"? That's a surprise.

Grant Hutchison

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