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Does Earth have two high-tide bulges on opposite sides? (2014)

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294 points imurray | 1 comments | 22 May 25 18:58 UTC | HN request time: 0s | source
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srean ◴[22 May 25 19:51 UTC] No.44066091[source]▶
The problem of predicting tides was so important that it attracted many Physics and Maths heavy weights. You can well imagine how important predicting tides would have been for D-day landing.

One related fascinating historical artifact is the special purpose analogue computer designed by Lord Kelvin in the 1860s based on Fourier series, harmonic analysis. Think difference engine in it's cogs and cams glory, but special purpose.

https://en.m.wikipedia.org/wiki/Tide-predicting_machine

Possibly one of the first examples of Machine learning, with Machine in capital 'M'. It incorporated recent tidal observations to update it's prediction.

Note that sinusoids are universal approximators for a large class of functions, an honour that is by no means restricted to deep neural nets.

George Darwin (Charles Darwin's son) was a significant contributor in the design and upgrade of the machine.

https://en.m.wikipedia.org/wiki/George_Darwin

Other recognizable names who worked on tide prediction problem were Thomas Young (of double slit experiment fame) and Sir George Airy (of Airy disk fame).

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1. TomK32 ◴[23 May 25 05:24 UTC] No.44070084[source]▶
The Battle of Clontarf on April 23rd 1014 springs to mind. While the high tide was of favour for the invading Vikings (who had already founded and still ruled Dublin) at 5:30 in the morn, the battle lasted all day and the next high tide at 17:55 cut off their way to a nearby wood and many killed or drowned as their were pushed against the tide. The times were calculated in 1860 by Samuel Haughton.

There is of course an In Our Time episode https://www.bbc.co.uk/programmes/m0029qh3