Saturday, 21 February 2015

Back from the Indian Ocean




Day 3 - still no land. (That's me).
Can the open sea be so calm? Yes it was - for days
The most awe-inspiring thing I found about this trip was definitely the four days of cruising before we got to Madagascar from Durban, having flown up from Cape Town. There is just something unsettling about a constant 360 degree view of nothing but the deep blue sea.  And a lovely blue it was: reminded me of bottles of Quink ink years ago, color Royal Blue.  Even more amazing: in some parts the ocean is 5 miles deep.  Can that be possible?  It got me thinking about gravity.  I can buy the part about the continents not falling off the planet, after they are solid and go through right to the middle, if you want to dig down.  But the water? How come this weight of water just doesn't fall off?  Didn't cost me any sleep though, just love the slight rocking feeling even on a big boat. More anon..  got family visiting this week-end.

7 comments:

  1. That is a beautiful shade of blue!

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    1. I am delighted to report that it was exactly this color. The camera doesn't lie.

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  2. Lovely photos! You are a better photographer (and subject of photography) than you are a geologist. (I am neither a photographer or a geologist--so you have a leg up on me). The continents and the sea beds are not solid all the way through. Plate tectonic suggest that the earth's crust is a series of plates that float over a semi-molten plastic asthenosphere, part of the mantle. Further down is a fully liquid iron outer core, then a solid iron inner core. The edges of the plates are the earth's earthquake zones.

    http://scitechdaily.com/images/Scientists-Probe-Earths-Core.jpg

    http://en.wikipedia.org/wiki/Plate_tectonics


    The water is indeed falling, but in the only direction that it can, toward the center of the earth. The only way that it could fall off the earth is if something with more mass came close to the earth and caused the water to fall away. We can see this action with the moon. The moon does not have enough mass to cause the water to fall away from the earth, but it does have enough mass to cause the water to fall up hill in what we call the tides. In high tide the water has moved "up" the beach. The moon it self and all the orbiting satellites are constantly falling toward the center of the earth, but as the body falls towards the center of the earth, the center of the earth moves slightly and the body misses, and so orbital mechanic is simply a smaller body trying to fall into a larger body and the larger body moving out of the way before it hits. The two bodies get locked into a system relative movement. So it goes with the earth around the sun and the sun around the galaxy....and I am bull shitting myself into a corner here.

    Another thing to think about regarding your 5 mile ocean depth, 5000 miles north east of where you were at is a 5.5 mile high mountain known as Everest. We think of the earth's surface as being highly irregular but when looked at in scale, it is actually smoother than a billiard ball.

    Anyhow no need to worry about anything falling off the earth. If you must worry, worry about things falling into the earth. Far bigger threat.

    Tell us more about your trip.

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    1. Ok, I remember the molten core bit but you lost me later - fancy the earth knowing how to get out of the way if something big is coming towards it (??)
      Anyway, as you say, there are more pressing concerns to worry about.

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    2. My explanation was a bit faulty. It is not that the Earth or any other planet is smart enough to move out of the way, it is that by chance that a natural body gets pulled in an orbit by being close enough that it is attracted to the planet but the relative motions are such that the orbiting body keeps falling to the surface but has enough tangential velocity to the surface that it over shoots the surface and just keeps falling. Here is a simple explanation, just read the first paragraph or so and don't worry about the math.

      http://my.execpc.com/~culp/space/orbit.html

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  3. Lovely photos! I adore being at sea on a cruise - despite the 360 view of the water. It's so peaceful and relaxing. Enjoy!

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    1. It was just marvellous. Can't wait to go again.

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