I'm not sure this actually provides the right perspective, in the sense of a useful intuition. Taking anything from the part of the Earth we live in (essentially, the troposphere plus the upper part of the crust) and visualizing it as a sphere will make it look small, because the troposphere + upper crust is a fairly thin shell, so doesn't take up a lot of volume when visualized as a solid sphere next to the earth.

The first thing I thought when I saw is image was that I would love to see an animation of the sphere collapsing and refilling the oceans, etc. Assuming the animation simulated actual gravity and water fluid dynamics, I wonder how long it would take and what it would look like? (That is, the initial reflooding, reforming of rivers, clouds and ice caps, and so on.)

Another interesting perspective: Earth's atmosphere is about five miles thick. Yes, it trails off exponentially and airplanes can fly and people can breathe (sort of) at 30,000 feet. However, were it uniformly as dense as it is at sea level (i.e. the atmosphere most of us are familiar with), it would fit in about five miles.

If you somehow started from this state, how long would it take the wave to reach the opposite side of the planet?

How likely is it that this sphere of water actually collided with our Earth billions of years ago? What is the possibility of even more such "water meteoroids" flying around nearby galaxies?

Another related perspective on earth oceans. Take a thimble of water and pour it into the ocean. Allow sufficient time for it to evenly mix. Now scoop a new thimble of water out of that ocean. Your new thimble will have several molecules from the original thimble of water.

Orders of magnitude and all that. To me though this shows how connected all of our resources are and how dangerous pollution can be.

Does it include all the water trapped in material of the mantle?

Interestingly, there is an estimate of the size of a sphere containing the water of the world's seas in Twenty Thousand Leagues under the sea:

"THE PART OF THE planet earth that the seas occupy has been assessed at 3,832,558 square myriameters, hence more than 38,000,000,000 hectares. This liquid mass totals 2,250,000,000 cubic miles and could form a sphere with a diameter of sixty leagues, whose weight would be three quintillion metric tons."

According to Google and Frink, 60 leagues is less than 1/4 of the 860 miles estimated here; I'm not sure how much of that is due to the smaller scope of the estimate in Verne's book.

This seems geared to make the amount of water on the planet look small, but it backfired for me.

I still remember the first time I flew over Lake Michigan, and my mind was blown at the impossible scale of all that water.

In this image, most people compare the water to the Earth. Nice, homey, medium sized Earth. In comparison, the water looks tiny.

I was drawn to that far tinier lake to its right, which once blew my mind. Comparing the lake to the big wet globe feels like skipping a few steps in Powers of Ten (or Gurren Lagann).

All I know for sure is that my poor human brain sucks at scale. "Bigger than I understand" arrives far too soon.

Nice work. It would be fun to see a comparison of the sphere containing Earth's water against a sphere of Earth's [relatively-]habitable area (say, the cumulative mass between the average depth of the sea-floor to the average height above sea level (of all exposed land massess)). For your intents, it could be a meaningful comparison in conjunction with you recent works. Thanks for sharing!

That's really not a lot of water, huh... And even less of it is directly consumable or even usable. This actually makes me think that mining asteroids for frozen water might not be such a bad idea (although it would still need to be purified)...

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It would be fascinating to see in separate 'spheres of water' the make up of all the oceans, all the atmospheric moisture, etc.

It is what it is.

Terrific