Thursday, August 26, 2010

Give me the Earth, cut it up, and I'll give you a nautical mile!

We approached the centre of the rise today. There has not been a lot to do since we started collecting multi channel seismic data. Maybe when we start recovering the OBSs I'll get to go up to the deck more often. We did sight a pod of whales today, though. This was a first for me. The whales were far off so I couldn't make them out very well. All I saw was the jet of water they made ever so often. Apart from this exciting event all I have been doing during my watch is looking at the monitors, recording OBS crossings and thinking about how long it'd take to get to the next site. I keep asking myself, "How long will it take before I can take my eyes off the paper I'm reading and record the next crossing? "

But things are different on the Langseth. I am used to working with distances in kilometers, I am Nigerian and we inherited the British system. Now I get to the United States and I have learnt to intuit the Mile. I run in miles, I drive in miles, Google navigator feeds me distances in miles. I get it. Now I have to get used to two new units, distance in "nautical miles" and speed in "knots". That's how sailors of old measured distances and speed, and although we have distance conversions, we still measure speed in knots on this research vessel. So I try to dig out conversions, run a couple of google searches, and voila! I discover very interesting history on the definition of the distance. I learnt during my search that both units of distance, the nautical mile and the kilometer were both defined based on the Earth. The nautical mile is actually an English system and the meter was defined by the French. The nautical mile you get if you cut up the earth in half at the equator and divide the circumference of the circle you get into 360 degrees, then each degree into 60 minutes. A minute of arc will then be 1 nautical mile. Same thing for the kilometer: you cut up the Earth. This time you cut it from the North pole, make it pass through paris (for historical reasons) and then measure the distance from the North pole to the equator, divide by 10,000 and you get 1 kilometer.

I see now. The ship travels at 5 knots. The knot? A very convenient measure of "nautical"speed: 1 nautical mile per hour. Nautical, anything relating to navigation. We navigate on the seas. The Earth. The distances make sense. 1 nautical mile ~ 2 kilometers ~ 1.2 miles. I am thinking to myself. If I run at my average running pace - I do have a best time, but Nike plus tells me I run ~ 9' 30''/ mile - how long will it take me to run round the world? I do the math. There are (360 * 60) nautical miles to run. Those miles give ~ ( 360 * 60 * 1.2) US miles. At my average running pace it'd take me ~ 237, 000 minutes. That's ~ 5 months and 12 days. I think I'll put off running round the world. Its a long night. I'm done with my watch and I want to return to bed, but I begin thinking about why we have to cut the earth into 360 parts. why 360 and 60? I am sure there are interesting reasons.

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