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All of Earth's water in a single sphere (2019)

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Re: All of Earth's water in a single sphere (2019)

#241

Post by outop »

nwiswell wrote: post #111
oorza wrote: post #98

Earlier 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…

The picture already answers this question. If the earth was a bowling ball the blue sphere would be much bigger than a single drop, maybe slightly bigger than a popping boba, the size of a small grape?

Re: All of Earth's water in a single sphere (2019)

#243

Post by Kaibeezy »

hoseja wrote: post #227
sfink wrote: post #59

I 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.

It is quite incredible that there is just enough water for a continuous ocean and also dry land, not either just a couple ponds or a waterworld.

Oceanus's ocean tosses with slow, tall waves, beneath a pale blue sky. The colonists live in tall cities of steel and concrete with buildings sealed against the planet's harsh environment, on platforms floating on the planet-wide ocean. They spend their time pursuing art, leisure, and spiritual fulfilment, while automatic machines take care of their material needs.

Re: All of Earth's water in a single sphere (2019)

#244

Post by jvm___ »

aspectmin wrote: post #151
RIMR wrote: post #123

Earlier quoted context omitted.

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.

An interesting exercise is to do this exact same calculation with the atmosphere.

It's fun to scale down the Earth's depth to a 8 metre long measuring tape on the floor and then having kids guess things lik, how deep is the ocean, how deep is the deepest hole we've ever dug, how high is the atmosphere.

Adding in how far of a drive is it to X place or how far of a walk is it, is also fun.

Re: All of Earth's water in a single sphere (2019)

#245

Post by keepamovin »

Sparkyte wrote: post #76
kevinkeller wrote: post #32

Largest 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-..…

We could probably terraform Mars if we crashed Europa into Mars.

And then wait 160 million years for the planet to settle. I like your long term thinking.

Re: All of Earth's water in a single sphere (2019)

#246

Post by keepamovin »

sfink wrote: post #59

I 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.

Mars is the same, right? Just the water is locked 20 - 200km beneath the surface from recent discoveries.

Re: All of Earth's water in a single sphere (2019)

#247

Post by Turneyboy »

jgtrosh wrote: post #218
Turneyboy wrote: post #217

Ok I don't mean to be pedanntic but a sphere is just the boundary of a ball. If we are trying to capture volume we should be talking about balls of water.

Counter pedant: a ball is indeed what you get when, as in TFA, you put water “in a sphere”

I agree. It's a volume of water bounded by a sphere. I'm just being pedantic about the common use of the word in this thread.

I'm also somewhat surprised no one else was being pedantic about this. I expect better from HN :)

Re: All of Earth's water in a single sphere (2019)

#248

Post by Symmetry »

dredmorbius wrote: post #183
hn_throwaway_99 wrote: post #178

Earlier quoted context omitted.

Does any of that water, though, ever make it onto the Earth's surface? I'm guessing not, or only miniscule amounts over geologic time through volcanism. For all intents and purposes, I think only counting "surface" water is more useful and intuitive. It's essentially any water that can participate in the hydrologic cycle on Earth, and that water locked beneath the crust doesn't really "matter" for what I think the in…

The fundamental problem with complex phenomena is in defining the domain(s) of interest. If we want to talk about the total amount of H2O around, on, or in the Earth then inclusion makes sense. If we want to talk about water interacting with the surface environment (atmospheric, sea, ice cap, fresh, and subsurface aquifers and tectonic water), then splitting those into distinct categories probably also makes sense. I…

Earth is lucky to have a strong magnetic field and ozone layer limiting the loss of hydrogen to the solar wind. Mars, for example, has lost much more of its allotment.

Re: All of Earth's water in a single sphere (2019)

#249

Post by Zobat »

yardstick wrote: post #214
CodeWriter23 wrote: post #24

I think this is kind of useless information unless presented with other spheres for humans, structures, animals, plants, forests etc. for comparison. And ants.

This was my first thought too. I had no idea where to start. ChatGPT had a rather impressive looking “proof of work” that put all living humans into a 976m-diameter sphere, compared to the ~1384km-diameter sphere. Ie ~1km human sphere and 1,384km water sphere.

Wolfram Alpha had "us" making a 966 m sphere.

https://www.wolframalpha.com/input?i=estimated+total+volume+...

Which has a link that gives us the radius.

https://www.wolframalpha.com/input?i=4.73%C3%9710%5E8+cubic+...

Re: All of Earth's water in a single sphere (2019)

#250

Post by openrisk »

If you could squeeze the Earth's atmosphere into a ball of similar density it would be more or less of size of the middle sphere (all the oceans only weigh 270 times as much as the atmosphere [1]).

So there you have it: the key ingredients all life depends on are but a tiny boundary layer of water and air, stretched thinly between solid rock and the hostile emptiness of outer space.

The grand challenge of our sustainability is, indeed, how much can we (humans) perturb this extraordinary complex boundary layer without inducing runaway dynamics that we (or rather, future generations of us) will not particularly like.

[1] https://www.sciencefocus.com/science/how-much-does-earths-at...

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