All that talk about time in last Saturday’s article (19th October), the ‘Palace of Time in Jerez de la Frontera’, reminded me of when Julie and I first arrived in Puerto de la Duquesa. One of the first things I noticed was that the sun appeared to be at its zenith a lot later than noon. I knew about British Summer Time of course, although I think that is unnecessary; If you want more daylight get up earlier. Anyhow, the local time in Duquesa seemed to be totally out of sync.
I find that sort of thing discombobulating so I set out to discover what was going on. I took a straight piece of wood, a compass, a clock and a plumb bob down to the beach one day and appropriated a patch of sand. I set the post up vertically and then marked off magnetic south using a small stone set a few feet from the stick. Some small children watched silently. Declination in Spain (the difference between magnetic south and true south) in the year 2000 was only 32 minutes west, so I ignored that. Then I waited. Sure enough when the stick’s shadow was shortest, it’s shadow pointed south. I found that somewhat reassuring. The time according to Timex was 14:21.
I could check that figure by taking the longitude of Duquesa (50 degrees 13 minutes west) and calculating the time it would take the sun’s shadow to travel that distance at the rate of 15 degrees per hour. Twenty one minutes, close enough.
The Greenwich meridian passes through Spain a few kilometres east of Valencia and the furthest point west on the Iberian peninsula is Cabo da Roca at 9 degrees 30 minutes west so technically the whole of Spain should observe GMT. Where did the extra hour come from?
Spain did adopt GMT on the 1st January 1901. It turns out that in 1940, Franco changed the time zone to correspond to Central European Time (GMT +1), the time zone used by Germany. Presumably so that he could chat to his mate Hitler and not miss a pre-booked telephone call. After the war the time zone in Spain was not changed back and it has been GMT +1 ever since.
So, problem solved, although I still feel discombobulated after nearly twenty years. (What a treat, using that word twice in the same article).
I have just made a cup of tea and, while waiting for the kettle, I started to ponder, as you do. At our latitude, how fast are we travelling through space due to the earth’s rotation? Back to the spreadsheet. The earth’s circumference at 36 degrees 21 minutes north is about 26,122 kilometres and the earth rotates once every 23hr 56mns. So we are whizzing around at 1,088 kph.
I have nearly finished my cup of tea and I have one more factor to throw into the pot. The earth’s orbital speed around the sun, which is 107,826 kph. As the earth rotates there are only two points where you will be travelling at exactly that speed; one when you are head on to the direction of travel, and another when you are facing away from the direction of travel. Now we already know from the above ponderings that at midnight we are facing away the sun, and at noon we are facing the sun so that will be when we are travelling at only orbital speed through space, 107,826 kph. Half way between those points at 6am, we will be travelling at orbital speed plus rotational speed, 108,914 kph and half way between noon and midnight, we will be travelling at our slowest speed, 106,738 kph. Fascinating isn’t it.
By the way, don’t forget to put your clocks back next Saturday the 26th October.
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Submitted by Moira on 23 Oct 2019
Spain originally was GMT - according to history Franco changed the time during the war to one hour ahead to be the same as the rest of Europe - an arrangement with Hitler!
Nick has lived and worked in Andalucia for over 20 years. He and his partner, Julie Evans, have travelled extensively and dug deep into the history and culture, producing authoritative articles on all aspects of the region. Nick has written four books about Andalucia and writes articles for other websites and blogs.
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