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If you collected all of Earth’s water into a sphere, how big would it be?

SystemSystem Member, NoReporting Posts: 178,019 Arc User
edited May 2012 in Ten Forward
Imagine the Earth in your mind's eye. Now round up all the water on the planet into a sphere (we're talking oceans, icecaps, atmosphere, everything — even the water bound up in you and me). How big do you think that sphere would be compared to the Earth?

Got your answer? Our water sphere would have a diameter of 1,385 kilometers (about 860 miles). A sphere this far across would have a volume equal to about 1,386 million cubic kilometers (roughly 332,500,000 cubic miles). Those might sound like big numbers (and they certainly are big numbers) but wait until you see this sphere beside the Earth.

http://img.gawkerassets.com/img/17lzydgufxz34jpg/original.jpg
Post edited by Unknown User on

Comments

  • Archived PostArchived Post Member Posts: 2,264,498 Arc User
    edited May 2012
    looks about the same size as the moon in Star Trek Online. :P

    And completely unbelievable to be honest. There HAS to be more water than that present on the entire planet.
  • Archived PostArchived Post Member Posts: 2,264,498 Arc User
    edited May 2012
    If that is right it looks quite surprising.

    It does look wrong when you first look at it but i guess its hard to tell. looking at the earth that small its hard to gauge how deep the oceans would be if the bubble burst so to speak.
  • Archived PostArchived Post Member Posts: 2,264,498 Arc User
    edited May 2012
    The deepest ocean point on earth is under 11 km. The earth's radius is 6,357 km. Even if the entire earth were covered in ocean to that depth all the water would be a sphere about 1100 km accross, about 685 miles - less than half the width of the continental US, it comes up more than a hundred miles short of New York to Chicago. And that is a gross overestimate, obviously.

    The average depth is only 3790 meters. If the entire earth were covered in ocean to that depth, the sphere is now only 785.5 km, or 488 miles. But only 71% of the earth is, so that brings us down to a sphere 700 km across, or 435 miles, about the distance from New York to Akron Ohio.

    Of course, that's only salt water. Adding all the fresh water in the world, including permafrost and the ice caps, is a 3% increase in volume, bringing it up to 707 km... the extra 7 km won't even get you out of Akron. The OP's reference also includes atmospheric water (not a huge increase) and geological water tied up in rocks and earth's interior. The io9 article it comes from has a final figure about 20% higher than mine, probably a combination of geological water and using a better average ocean depth than I got off wikipedia.

    Remember: The difference between the tallest mountain and the deepest trench, as a percentage of the earth's diameter, makes the planet smoother than a regulation billiards ball, and only slightly rougher than the most high grade industrial bearings. The oceans, the biosphere, even the atmosphere, are all just a very thin film on a surprisingly smooth sphere.
  • Archived PostArchived Post Member Posts: 2,264,498 Arc User
    edited May 2012
    hevach wrote: »
    snip.

    Man i so wish the forum had a +1 button right now. :D :cool:
  • Archived PostArchived Post Member Posts: 2,264,498 Arc User
    edited May 2012
    Fun fact: It's thought that Europa has twice as much water as the Earth. URL="http://solarsystem.nasa.gov/planets/profile.cfm?Object=Jupiter&Display=Sats"]LINK[/URL
  • Archived PostArchived Post Member Posts: 2,264,498 Arc User
    edited May 2012
    Big enough to hold it.


    ....hey....(tap, tap)...is this thing on?(microphone feedback)
  • Archived PostArchived Post Member Posts: 2,264,498 Arc User
    edited May 2012
    hevach wrote: »
    Remember: The difference between the tallest mountain and the deepest trench, as a percentage of the earth's diameter, makes the planet smoother than a regulation billiards ball, and only slightly rougher than the most high grade industrial bearings. The oceans, the biosphere, even the atmosphere, are all just a very thin film on a surprisingly smooth sphere.

    The difference between the tallest peak and deepest trench is about 20 km on a sphere with a radius of about 6300 km--in other words, a variation of one third of one percent.

    All this talk about a sphere of water reminds me of the Voyager episode "Thirty Days" http://en.memory-alpha.org/wiki/Thirty_Days_%28episode%29 where a Delta Quadrant society had siphoned all of the water from a planet to create a liquid planetoid which they named "The Waters".
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