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New Estimates Say Earth's Oceans Smaller Than Once Believed 263

Posted by timothy
from the deeper-than-my-love-for-you dept.
Velcroman1 writes with this snippet from Fox News: "Using lead weights and depth sounders, scientists have made surprisingly accurate estimates of the ocean's depths in the past. Now, with satellites and radar, researchers have pinned down a more accurate answer to that age-old query: How deep is the ocean? And how big? As long ago as 1888, John Murray dangled lead weights from a rope off a ship to calculate the ocean's volume — the product of area and mean ocean depth. Using satellite data, researchers from the Woods Hole Oceanographic Institute set out to more accurately answer that question — and found out that it's 320 million cubic miles. And despite miles-deep abysses like the Mariana Trench, the ocean's mean depth is just 2.29 miles, thanks to the varied and bumpy ocean floor."
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New Estimates Say Earth's Oceans Smaller Than Once Believed

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  • by cytoman (792326) on Wednesday May 19, 2010 @05:23PM (#32270944)

    Using satellite data, researchers from the Woods Hole Oceanographic Institute (WHOI) set out to more accurately answer that question -- and found out that it's 320 million cubic miles.

    So, what were the earlier estimates? I'm on Slashdot => I did not RTFA.

  • Evaporation? (Score:4, Interesting)

    by cytoman (792326) on Wednesday May 19, 2010 @05:26PM (#32270962)
    Do they consider the effect of evaporation? Earth loses some of its atmosphere to space constantly and it's not too improbable that some water vapor is also lost in this way...
    • by geekoid (135745)

      What? what water bleeds into space?

      • Re: (Score:2, Interesting)

        by Narcocide (102829)

        Don't panic, it's not very fast, but we DO need to encase it, ourselves and the sun in a giant Dyson Sphere [wikipedia.org] soon to mitigate the problem.

        • by Pharmboy (216950)

          Hah! I could gum through that cheap diamondillium Dyson Sphere with my dentures behind my back! What we need is my patented ultra hard Diamondium [theinfosphere.org]!

      • by cytoman (792326)
        Better believe it - what with anthropogenic global warming and all...the water will all just boil away and earth will become one giant desert :-(. Just give it enough time, that's all.
      • by cytoman (792326)
        Isn't that why Mars is dry?
        • by thms (1339227) on Wednesday May 19, 2010 @05:46PM (#32271234)

          Yes, IIRC by the same mechanism Venus has a lot of relatively heavier elements (Carbon, Oxygen, Sulfur), but barely any Hydrogen if you compare it to Earth and count the oceans as part of the atmosphere.

          Water (gas) is split by solar radiation higher up, and the light hydrogen is carried upwards, and some of these particles bump into each other and often enough these bumps add up to escape velocity for one particle. Supposedly solar winds also play a significant role, and as Mars and Venus don't have a magnetic field anymore to protect them, over the eons all the hydrogen was lost. One more factor for the Drake Equation!

    • I was thinking the same thing. We should really start a project to refill the oceans, based on how the oceans have shrunk and are evaporating. We should give this project a catchy name.....say, global warming?
    • Re:Evaporation? (Score:5, Interesting)

      by w0mprat (1317953) on Wednesday May 19, 2010 @07:03PM (#32272222)
      While it's true we lose some gas at the top of our atmosphere, earth is probably sufficiently large that we have a net growth due to meteorite bombardment. (By every measure I've heard of the earth is supposedly getting heavier). We may take on extra H2O from water ice in meteroids?
  • by MyLongNickName (822545) on Wednesday May 19, 2010 @05:29PM (#32270996) Journal

    Well, it was more volumous. But all those sponges soaked up so much.

  • by Edisman (726822) on Wednesday May 19, 2010 @05:34PM (#32271054)
    For all you metric fans out there, the volume 320 × 10^6 cubic miles is approx. 133.4 × 10^7 cubic km with an average depth of 3.69 km.
    • by melikamp (631205)
      My measurement system is based on furlongs, fortnights, and frags, you insensitive clod.
    • by Red Flayer (890720) on Wednesday May 19, 2010 @05:41PM (#32271142) Journal

      For all you metric fans out there, the volume 320 × 10^6 cubic miles is approx. 133.4 × 10^7 cubic km with an average depth of 3.69 km.

      Yes, but that's meaningless to most people, it's a VLN without context. For all you fans of real, visceral numbers you can relate to, that volume (1.33 x 10^9 km^3) is approximately equal to the amount of water in the earth's oceans.

      Hope that helps you to understand the magnitude of the number. Glad to be of service.

      • by 4D6963 (933028)
        Another perhaps more meaningful way to put it is that it's the same volume as a sphere with a diameter of 1366 km (roughly the size of Iapetus [wikipedia.org]), knowing that the Moon has a diameter of 3476 km, which means a sphere with 16.5 less volume than the Moon.
      • by ras (84108)

        So, the oceans contain roughly 1 cubic mega meter of water. That is an easy number to remember.

        Oh, how I love metric.

      • by StikyPad (445176)

        Sorry, that's too vague and 1 EO (Earth's Oceans) sounds small.

        • Olympic Swimming Pools: 5.32e14 total -- 79,435.5 per person* (depending on pool depth)
        • Oil Barrels: 8.36544833e18 total -- 1,249,086,310 per person
        • cups: 5.62158127e21 total -- 839,385,998,000 per person

        * Using World Bank estimate for 2008: 6,697,254,041 people

      • Re: (Score:3, Funny)

        by viking80 (697716)

        Well, if you put all the water after each other, it would reach from here to the moon and back. maybe that helps us grasp such a big number...

      • For all you fans of real, visceral numbers you can relate to, that volume (1.33 x 10^9 km^3) is approximately equal to the amount of water in the earth's oceans.

        Nice try, but

        1. The Tao of numbers states that the numbers that are real cannot be counted, and
        2. visceral numbers appear to have an imaginary component since in all of known physics and chemistry, numbers do not of themselves affect the gut, therefore
        3. the relationship being referred to is an imaginary relationship (not uncommon on slashdot, as evidenced by the occasional mention by a slashdotter that he has a gf), and
        4. such imaginary relationships cannot be counted upon.

        In short, any earthling who thinks he c

    • And to us fans of "classic" metrics, we have:

      5.34 x 10^14 olympic sized swimming pools (534 trillion)

      1.24 x 10^13 Libraries of Congress (12 trillion)

      4.475 x 10^19 firkins (45 quintillion)

      And the depth is equivalent to 18.32 furlongs or 8.2 Empire State Buildings. You're welcome.
    • by tsalmark (1265778)
      The original article is in Metric, Fox just buggered with the numbers. http://www.whoi.edu/page.do?pid=7545&tid=282&cid=74755&ct=162 [whoi.edu]
    • by fnj (64210)

      Actually it would make more sense to use base units when expressing such large quantities in SI units, and to normalize the numeric scientific notation.

      1.334 x 10^18 m^3

  • by schmidt349 (690948) on Wednesday May 19, 2010 @05:45PM (#32271216)

    2.29 miles isn't even 1 league! I thought the ocean was 20,000 leagues deep!

  • Could these numbers be confirmed by gravimetric measurements of the tides? The moon, sun, and to a very small extent the planet Jupiter, raise tides in the ocean and induce a gravitational moment. It seems like we could measure that and use it to approximate the mass of the oceans and therefore their volume, though off the top of my head I'm not sure about the details.
  • Erm, 12,000 feet is pretty damn deep water.

  • by Itninja (937614) on Wednesday May 19, 2010 @05:53PM (#32271326) Homepage
    Do they include the extreme edge of the oceans (i.e. beaches) where the 'depth' is only a few millimeters? Or do they go out to sea a standard distance before they start measuring?
  • by sharkey (16670)
    We must stop global warming!! Our oceans are getting smaller, we, um, need to, uh, what?
  • I never thought I'd see the day when /. links to fox news.
     
    It's a fairly well written article though. I'd say it's head and shoulders above anything they've linked to on Tom's Hardware, but that's not saying much.

    • Let me be the first to say:

      SlashFonzieDot ------------->
                          Shark

    • by Spatial (1235392)
      That said, it was funny to see this on Slashdot:

      the ocean's volume — the product of area and mean ocean depth

      Next week we'll have multiplication explained to us, I suppose.

      • by Hadlock (143607)

        This is my favorite:
         
          The trend toward a progressive lowering of volume estimates is not because the world's oceans are losing water.

  • by fahrbot-bot (874524) on Wednesday May 19, 2010 @06:32PM (#32271880)
    Having lived their entire lives without seeing the ocean, two old women take a trip to the Pacific coast. Upon arriving on the beach, one looks out toward the horizon and says to the other, "That's funny, I thought it would be bigger."
  • 5.59297599 × 10^18 hogsheads 3.52357487 × 10^20 US gallons 1.33381818 × 10^21 litres

Entropy isn't what it used to be.

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