Originally published at: If all the world's water were a sphere, it'd be about as wide as Alaska - Boing Boing
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This was basically the premise of a Star Trek: Voyager episode.
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IIRC, if you shrank the earth down to the size of a cue ball, with all its ocean trenches and mountains, it would actually be smoother than we could make the cue ball. So given that, yeah, the deep oceans aren’t really that much compared to the rest of the size of the earth!
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Yes, you recall correctly. Thanks for the info; I found one source.
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I wonder if they took pressure into account, as a liter of water at the surface is not the same as a liter of water at the bottom of the ocean. Also, of a sphere of water were made, would it have enough density to have gravitational compression at its core, and would the surface boil away?
It does give an idea of now many comets would have been involved in transporting water and hydrocarbons to the mostly iron-nickel primordial earth, though.
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There’s about as much water again bound up as hydrated minerals in the Earth’s Mantle.
No one is entirely sure how it got there. it might be primordial water left over from the creation of the planet or it might be water that has been taken down by subduction of ocean crust. Some of that water comes back up again as it helps drive melting of the Mantle at shallow depths; but some of it is presumably carried all the way down to wherever it is that subducting plates go - and that is still something of a mystery.
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that is a very small amount of freshwater for the whole planet, isnt it? I dont like that.
I guess the compression is small enough to be neglectable, its around just 2% at 3km (average depth)?
e/ (switched percentage to make actual sense)
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Yes, but the main problem isn’t the absolute amount, it’s all the places where we’re withdrawing it faster than stocks replenish (esp. aquifers and rivers) or contaminating existing supplies of fresh water. Water cycles in and out of the atmosphere constantly, and evaporated water from salty oceans rains down as freshwater a week or two later.
Overall, as a society, we are very, very, very far from using water efficiently. There’s lots of room for improvement, and no fundamental reason (beyond poor coordination and planning) that we can’t meet our water needs indefinitely.
Keep in mind that about ~1/3 or water use is for cooling power plants, so moving to more green power and using less power overall also saves a huge amount of water. Another ~1/3 is for food production, and not only are there ways to make farming less water intensive, but in most cases the dietary changes we know would make us healthier are also the ones that have the most impact on water use. (Note: Water intensity estimates of food production are mostly rainwater, so it’s often not trivial to instead capture that water for other uses. It’s still the case that the same rainwater that can grow crops to feed cows could also grow crops to feed many times more humans).
It doesn’t help that a lot of the technologies that could improve domestic water use the most are not only not the ones that get subsidized (things like showerheads and toilets), they’re often disallowed by outdated (interpretations of) building codes. You want to capture and filter rainwater and fog, install a recirculating shower, use graywater to flush your toilet, and filter the rest of the greywater to wash clothes and water plants (like I do in my next home)? That’s all doable today with commercially available (though relatively young) tech. Depending on where you live it can be difficult or impossible to get permission to build it or find a contractor who understands it.
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Water is not terribly compressible, so I suspect the volume wound not change that much.
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thats the main reason why I wrote “dont like it”.
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I know, and I agree. I was trying to highlight that we have lots of things we could be doing today to not even need to touch that stock of freshwater, without giving up much of anything in terms of actual experience in daily life. It makes a huge difference where my freshwater comes from, not just how much I use. With the right capture and filtration tech installed, even a house in somewhere dry like Las Vegas could replace something like 90% of its water consumption with rainwater landing on the roof that (after use) ends up flowing into the same ground it would have ended up in anyway.
If that seems ridiculous, consider that a 2000 sq ft house there receives ~5k gallons of rainwater on the roof a year on average. Capture and treat and store it. Use it for a recirculating shower, 5 gallons almost regardless of shower length. Filter that greywater and use it to wash clothes and dishes. Filter that greywater and use it to flush the toilet. That blackwater then goes into green septic tanks that release the treated water into the soil. Today we do none of that, and the average household in the area uses on the order of a hundred gallons or freshwater per person per day, while Lake Mead gets lower and lower.
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Cool, so if we could hook up a really monstrous fusion torch drive to, say, Pluto and Eris, and they contain as much water as we think they do, we could terraform Mars with one quick, violent, and epic collision. Now, how to get the Kickstarter going…
Also not taken into account is the habit water has during freezing to actually expand in volume as it forms crystalline lattices and such. Er. I’m overthinking this.
As far as the amount of freshwater is concerned, it’s worth comparing it to the amount of organic matter that makes up the life forms which rely upon it. We tend to forget just how small we life forms are in comparison as well.
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If all the world were paper
And all the seas were ink,
If all the trees were bread and cheese
What would we do for drink? ~ anonymous
one of my favorite little doggerels, as a Papiermeister.
but seriously, that very small sphere representing fresh water is frightening!
indeed, what shall we do for drink?
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Break out the mead!!
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Chinese water attack panic, missile it.
as wide as Alaska
Wikipedia informs me that is 2,261 miles.
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