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Sea Gliders Show Underwater and Off-World Potential - Open Knowledge — LiveJournal

Nov. 25th, 2008

04:00 am - Sea Gliders Show Underwater and Off-World Potential

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Underwater gliders work by being buoyantly nearly neutral while near the water’s surface, so that they sink slowly down. Very slowly – full steam ahead is under one knot. As they sink, an internal weight is shifted toward the lateral direction the vehicle should go – if you want to go straight, just shift the weight forward to tilt the nose down a bit. Then to rise, pump an oil contained inside the hull into external sacks – this simple maneuver increases the craft’s volume, and thus lowers its density just enough that now the surrounding water wants to push it upward.

Original: craschworks - comments

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From:polyanarch
Date:November 25th, 2008 02:29 pm (UTC)

Awesome

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For the longest time scientists couldn't figure out how some sea-going species were able to cover such distances in short times on so little food. Working the problem, they realized that with the drag of the water the amount of energy they would have to exert to propel themselves along far outpaced the amount of calories they were taking in by almost an order of magnitude. Then some smart guy figured out they were doing this exact same thing. All of the sea mammals can easily use their abdominal muscles to compress their lungs and change their boyancy from slightly positive, neutral to slighly negative.

Instead of sinking like a rock or floating up like a balloon, these clever little creatures glided forwards in both the up and the down cycle.

Pretty neat huh? The same concept can be done with lighter than air ships as well.

Now I'm starting to think -did I read about this in your journal originally a year or so ago?
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