[HN Gopher] Tides are weirder than you think
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       Tides are weirder than you think
        
       Author : surprisetalk
       Score  : 34 points
       Date   : 2025-12-01 20:14 UTC (4 days ago)
        
 (HTM) web link (signoregalilei.com)
 (TXT) w3m dump (signoregalilei.com)
        
       | fhdkweig wrote:
       | https://www.youtube.com/watch?v=AxC770lpSLw shows one of the old
       | tide prediction mechanical computers briefly mentioned in this
       | article. It is effectively doing an inverse Fourier Transform,
       | summing all the various 30+ sinusoids that affect the tides.
        
       | wasting_time wrote:
       | Relevant xkcd: https://xkcd.com/3135
        
         | santoriv wrote:
         | Reminds me of the time that Bill O'Reilly argued on national
         | television that tides were inexplicable.
         | 
         | https://www.youtube.com/watch?v=NUeybwTMeWo
        
       | xg15 wrote:
       | > _Kelvin's machine automates the second half of that task. As
       | the pulleys spin, they pull on a common chain by the correct
       | amount for each of the calculated components. A year's worth of
       | tidal tables can be put together in half an hour, if you know the
       | components. Even better, you can "guess and check" the components
       | by comparing your machine's output to past records, and adjusting
       | the pulleys until you get something that works correctly._
       | 
       | I didn't know they already had machine learning and model fitting
       | algorithms in the 1800s, but here we are...
        
         | LoganDark wrote:
         | https://xkcd.com/1838
        
       | metalman wrote:
       | out the back door of my house, down through the field and woods
       | to the water is a 12 min walk at high tide, and another 12 min +
       | walk to the water at low tide, 53 vertical feet between the two.
       | I know ,not the slightest thing about tides, other than what my
       | senses tell me when walking the shore, and I suppose the
       | practicalities of beach walking along cliffs are similar to
       | planning and predicting arival times for ships loaded to the
       | maximum draft, the money to be made there bieng the motivation
       | behind the push to understand tides.
        
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