Helps one understand why pollution is such an insidious problem.
All of Earth's water in a single sphere (2019)
121–130 of 290 posts
Re: All of Earth's water in a single sphere (2019)
#122Sounds like the water moon from Iain M Banks "The Algebraist", quote:
"I was born on a water moon.
Some people, especially its inhabitants, called it a planet, but as it was only a little over two hundred kilometers in diameter 'moon' seems the more accurate term. The moon was made entirely of water, by which I mean it was a globe that not only had no land, but no rock either, a sphere with no solid core at all, just water, all the way down to the very center of the globe.
If it had been much bigger the moon would have had a core of ice, for water, though supposedly incompressible, is not entirely so, and will change under extremes of pressure to become ice. (If you are used to living on a planet where ice floats on the surface of water, this seems odd and even wrong, but nevertheless it is the case.) This moon was not quite of a size for an ice core to form, and therefore one could, if one was sufficiently hardy, and adequately proof against the water pressure, make one's way down, through the increasing weight of water above, to the very center of the moon.
Where a strange thing happened.
For here, at the very center of this watery globe, there seemed to be no gravity. There was colossal pressure, certainly, pressing in from every side, but one was in effect weightless (on the outside of a planet, moon, or other body, watery or not, one is always being pulled towards its center; once at its center one is being pulled equally in all directions), and indeed the pressure around one was, for the same reason, not quite as great as one might have expected it to be, given the mass of the water that the moon was made up from."
Re: All of Earth's water in a single sphere (2019)
#123I long assumed that the Earth is a "water planet" because water is mostly what you see from a distance. It wasn't until I did the math that I realized that is really about wet rocks in space vs dry rocks in space. Earth isn't made of water, it's just a damp rock. Or a bowling ball that you squirted a dozen times with a spray bottle.
The ballpark math is easy to do in your head too. The diameter of Earth is 8,000 miles, and the deepest point in the ocean, the Mariana Trench, is only 7 miles deep. It's immediately apparent that the oceans are tiny by comparison to the rest of the mass that is Earth.
Re: All of Earth's water in a single sphere (2019)
#124Does this include the water in all human made stuff like pools, tanks, etc and also water present in all organisms? Or is that negligible?
> This sphere includes all of the water in the oceans, ice caps, lakes, rivers, groundwater, atmospheric water, and even the water in you, your dog, and your tomato plant.
Re: All of Earth's water in a single sphere (2019)
#125Earlier quoted context omitted.
Closer to a bowling ball that picked up a drop of beer from your hands.
This didn't sound right, so I did the math. The volume of all water is 1,386,000,000 km^3, which is then 1.386e+21 liters, or right about the same number of kilograms. The mass of Earth is about 5.972e+24 kg. So the percent fraction by mass is 0.0232%. A "drop" is typically estimated at 1/20th of one mL, which is then 0.05 grams. We can estimate the mass of a small-ish bowling ball at 5kg, or 5000 grams. 0.05 / 5000…
Thanks. This really put it in perspective for me better than the image or other analogies!
Re: All of Earth's water in a single sphere (2019)
#126Does this include the water in all human made stuff like pools, tanks, etc and also water present in all organisms? Or is that negligible?
From TFA: "This sphere includes all of the water in the oceans, ice caps, lakes, rivers, groundwater, atmospheric water, and even the water in you, your dog, and your tomato plant."
Re: All of Earth's water in a single sphere (2019)
#127Earlier quoted context omitted.
We could probably terraform Mars if we crashed Europa into Mars.
It would make Mars warmer. It would melt all the ice and CO2. It would give Mars an ocean. Of liquid rock. This is assuming that it doesn't destroy Mars completely. There might be enough fragments to make Solar System dangerous place and destroy life on Earth. Europa is the size of our Moon. Colliding it with Mars would be similar to the collision that formed our Moon.
But would it stay on Mars? I thought the issue was there was no dynamo in the core, which lets solar winds strip it away. How long would it stay?
Re: All of Earth's water in a single sphere (2019)
#128Shouldn’t this say “surface water”?
Re: All of Earth's water in a single sphere (2019)
#129"Consider a spherical ocean..."
Re: All of Earth's water in a single sphere (2019)
#130Earlier quoted context omitted.
Freezing? Wouldn't it boil instead due to the low pressure?
i knew there would be someone to just try to get out of the answer by failing to just go with the spirit of the question by being pedantic. even my own attempt at dispel pedantry just allowed for even more pedantry.
I don't know what you wanted.
If you wanted to ask whether that amount can hold together and become spherical, then just by comparing to Ceres doesn't that make it plenty?
It's not crazy to interpret "hold itself together" as more complex and including vapor escape.