Can’t help but want to build that. Apparently all the mined gold in the world would fit inside a 5 m diameter sphere. Spheres are suspicious in hiding weight.
I thought it was an Olympic sized swimming pool.
All of Earth's water in a single sphere (2019)
51–60 of 290 posts
Re: All of Earth's water in a single sphere (2019)
#52Earlier quoted context omitted.
But would this sphere of water have enough mass to hold itself together as a sphere in space? Put aside it freezing into a ball of ice as a thought exercise.
Freezing? Wouldn't it boil instead due to the low pressure?
Depends on the temperature. At Earth-like temperatures, yes, it would. The transition between the two is around 175 K, give or take; below about 150 K ice is quite stable in a vacuum even over astronomical timescales; above 200 K it sublimates rapidly. (Surface liquid water is never stable in a vacuum or thin atmosphere regardless.)
The rate of evaporation ramps up exponentially, from ~irrelevant at the bottom of that range to fast at the top. (For a body of this size, any resulting vapor would be quickly lost at these temperatures, so the rate of evaporation is effectively the rate of water loss as well.)
This is why Jupiter can have icy moons (temperature ~100 K), but ice sublimates quickly on Mars (~200 K).
Re: All of Earth's water in a single sphere (2019)
#53... it's about as much water as this place https://en.wikipedia.org/wiki/Ceres_(dwarf_planet)
So, crash Ceres into Mars, and we have made a huge step towards terraforming?
Ceres could be taken apart with solar energy and rebuilt into a habitat much bigger than the Earth, never mind Mars. Ceres leads to the stars, Mars is just a dead end.
Re: All of Earth's water in a single sphere (2019)
#54I honestly find this extremely unsettling. There should definitely be more, though I don't really want our planet to look like Kamino
Re: All of Earth's water in a single sphere (2019)
#55Just a few quick calculations to make it more relatable... They say the smallest sphere of freshwater lakes and rivers amounts to 93,113 cu km. There are 1 bil cu m per cu km. With a global population of 8.2 bil people, that comes to 11,355 cu m per person. That's a 22.5 meter wide/deep/tall cube (or about 7 or 8 stories tall building). If we use the sphere that includes groundwater, 10,633,450 cu km. Then we end up…
Also.. the largest sphere has a radius of about 92 miles. It reaches to the edge of the atmosphere, and about 1/3 of the way to low earth orbit.
> The largest sphere represents all of Earth's water. Its diameter is about 860 miles
Should be a radius of 430 miles, no?
The image is very non-intuitive, IMO, because it's making the water appear so small compared to the entire planet (which, duh, obviously the water is only part of earth), but also drawing the planet that small really hides how friggin big the earth is!
Re: All of Earth's water in a single sphere (2019)
#56Earlier quoted context omitted.
Volume functions are not exponential. They are polynomial. (Fair point that people are lousy at estimating even polynomial functions, though...)
> They are polynomial I don't think this word means what you think it does. Or I don't. Exponents are just the number the value is raised. Squaring a value just uses an exponent of 2 where cubing uses an exponent of 3. Polynomials are x^2 + x + 1 type of equations. But admittedly, it has been 30+ years since I've thought about them at that level, so maybe I'm the one with fuzzy groking
"Polynomial" meaning x^n. "Exponential" meaning e^x.
Exponentials eventually grow much faster than polynomials, no matter what the exponent is.
I mean, look, in v = x^3, the "3" is an exponent. But it's not an exponential function because the variable isn't in the exponent.
Re: All of Earth's water in a single sphere (2019)
#57Largest ocean in our solar system isn't even on Earth, apparently: > ... Ganymede’s ocean is even bigger than Europa’s—and might be the largest in the entire solar system. “The Ganymede ocean is believed to contain more water than the Europan one,” he says. “Six times more water in Ganymede’s ocean than in Earth's ocean, and three times more than Europa.” https://www.scientificamerican.com/article/overlooked-ocean-..…
https://www.businessinsider.nl/earth-water-ice-volume-versus...
Ganymede vs. Earth is indeed very surprising!
Re: All of Earth's water in a single sphere (2019)
#58> 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. Does it include water in the mantle? ( https://www.bnl.gov/newsroom/news.php?a=111648 ) or other non-liquid water for that matter like hydrates (ebsom salts, etc)
Yep, it's quite misleading since the region where they looked for water at all is an incredibly thin layer on the outside of the planet, but they show it all as if it applied to all of the volume.
Re: All of Earth's water in a single sphere (2019)
#59I 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.
Re: All of Earth's water in a single sphere (2019)
#60Can’t help but want to build that. Apparently all the mined gold in the world would fit inside a 5 m diameter sphere. Spheres are suspicious in hiding weight.
I thought it was an Olympic sized swimming pool.
Close. About four of them, or a single 40-track one (the standard one has 10 tracks/lanes.)