Perhaps we take the earth's coordinate grid system, if we think about it all, for granted. But not so fast. Calculating latitude, the distance of a position north or south of the equator, involves trigonometry and calculating longitude, distance east or west of the prime meridian, demands an accurate clock.
A clock? Yes, a clock which tells the time at the prime meridian, the sun's set "starting point" as it moves across the sky, and your position on the earth. Long story very short, if it's Noon at the prime meridian and 2.00 pm at your position, you're at longitude 30° east. Why? Because the sun crosses the sky at a rate of 15° per hour, given 24 hours in a day and 360° in a circle (360° ÷ 24 hours = 15° per hour).
Simple enough math but how do you make the calculation without a good clock? Tricky, which is why Parliament offered an immense prize of £20,000 in 1714, over £2 million today, to anyone who could come up with such a device. John Harrison did so and accurate navigation became possible. But here's the thing.
Back in 1966, science prof John Habgood re-examined the Piri Reis map, compiled from ancient maps by the Turkish admiral of the same name in 1513. Hapgood discovered what he believed were accurate measures of longitude and latitude. If true, this is remarkable.
It means that the ancient maps used by Reis were made by people who understood trigonometry and had some kind of reliable clock. The first supposition is understandable, the 2nd century BC Greek mathematician, Hipparchus, is held to have invented trigonometry.
So Greek cartographers were able, at least in theory, to calculate latitude. But longitude? That takes a good clock and we all know these weren't invented until the 18th century. Or were they.
It means that the ancient maps used by Reis were made by people who understood trigonometry and had some kind of reliable clock. The first supposition is understandable, the 2nd century BC Greek mathematician, Hipparchus, is held to have invented trigonometry.
So Greek cartographers were able, at least in theory, to calculate latitude. But longitude? That takes a good clock and we all know these weren't invented until the 18th century. Or were they.
Here's Harrison's prototype clock:
A clock? Or something very like it, dating from the first or second century BC. Food for thought. Hapgood's suggestion in Maps of the Ancient Sea Kings is that there must have been a civilization prior to the Greeks who were skilled mathematicians and able to tell time to the degree required to calculate longitude. I find that fascinating.
Speaking of time, the Government's been shut down for a very long time and everyone seems a lot happier. Was there an advanced civilization before our own? I'd have thought that obvious.
Mercator,
LSP
14 comments:
The Byzantines had accurate "water clocks" and they may have been around before then. The question for mariners becomes one of portability because those water clocks were large and very heavy. It's interesting to speculate how ancient peoples navigated at sea. The RA Expedition and Con Tiki are examples of travel over vast distances in the ocean that didn't necessarily require the use of traditional navigation (with gizmos).
Yes, the Piri Reis map is an enigma to this day. My question is how on earth (so to speak) could the ancient Turkish admiral have determined the coastline of Antarctica (which also appears on his map and is relatively accurate) when it is widely accepted that this land feature is buried under a mile or two of ice as we speak, and has been buried under this same ice for 10,000 years or more?
Hmmmm? I want to know.
I once did a post on the Antikythera Mechanism. It also tracked the motion of celestial bodies and had functions that were unknown (at least at the time) to those examining the device via X-ray.
I view those days of invention as a few really smart people, and the rest obsessed with sex and violence. Well, not much different than today I guess.
Yes, the sextant was all about star positions and time of day. Magellen was one of the first to use it to circum-navigatge the globe? (Spelling be damned.)
Good water clock point, LL, and the Greeks certainly had them in antiquity. And it doesn't seem as if they couldn't have carried them about in boats. Interesting Con Tiki thing, too, and it shows that people could travel the seas with very primitive tech.
Still, the Antikythera Mechanism is remarkably sophisticated, outrageously so, and portable, which makes us wonder if there was some source of accurate, mechanical time keeping in very early antiquity. The tech was pretty much evidently there, that's indisputable thanks to the Mechanism.
Did it extend to clocks? If so, we don't have any evidence apart from what appear to be, if Hapgood et al are right, accurate measurements of longitude on ancient maps. And strong hints of the time keeping possibility in the Mechanism.
One line of thought postulates that a culture existed with advanced seafaring, navigational tech knowledge before the Greeks, who inherited the knowledge.
If true, we'd have to rewrite history.
Me too, Fredd. It's very puzzling and seems to show the existence of an ancient, comparatively advanced seagoing culture.
I threw in the Antikythera thing to show that, remarkably, the technology existed in early antiquity to produce accurate navigational devices. Some say this was inherited by the Greeks and the relic of a lost civilization which was able to map parts of the antarctic at around 10,000 BC. Comparable, when you think about it, to Gobekli Tepe.
Fascinating stuff. And I know, it involves boats but maybe in a good way?
Kid, we have to wonder. It seems that the Mechanism's OLD -- that it was made of low lead/tin bronze (typical of 5C BC and earlier) and possibly repurposed. Well, who knows. But it is remarkable, equivalent to "finding a Jumbo Jet in the tomb of Tutankhmen" or something like that.
My question is -- given the apparent ability to make a device of such precision, why not the ability to make a clock and thus calculate longitude, which we apparently see echoes of in ancient maps.
But what do I know, I'm just an LSP...
Pastor: yes, it probably involves 'space boats,' the kind that tend to shake one's faith in the Bible. Not that your faith, Pastor, you know, others' faith. I knows yours is rock solid.
Fredd, some people think that space boats/ufos would disprove the Bible and the Church. I don't get that. Say we'd been visited by hi-tech aliens in their "boats," who kindly gave us nav skills and clocks. Ok, fine. Thanks, aliens, well done. But what does that have to do with the existence of God? It'd just show his creative power.
But I know what you're thinking. Imagine the repair bills, the dock fees, the insurance, the maintenance and fuel costs of the Space Boat. I can see how that might shake a person's faith in a loving God.
Good point.
Clock, great question. I don't think the A device was self powered but driven by hand?
Kid, it seems to have been driven by a hand turned crank. Could it have been a nav device? Some say yes, and that it gave the longitude of the sun and moon. Remarkable if true.
Pastor: some suggest that those we call God and angels were just creatures from somewhere else with better tech; that we are assigning faith to aliens and not The Almighty.
But SEE? Your faith was not shaken at all, Like A Rock!
Yes, Fredd, petrine. We must stand firm on the rock. That doesn't mean a lot of bishops aren't space aliens from another dimension. Far from it, many of them are, consider the evidence:
http://lonestarparson.blogspot.com/2015/02/anglican-consultative-council-taken.html
All the celestial nav I have done used a clock. But I believe that Bowditch used the Lunar Occlusion method which did not use a time piece. Of course, when clocks became available everyone dropped the method like a hot potation.
Good point, OC. Maybe I was a bit forward on the clock thing but the Mechanism's precision seems to suggest the possibility. Still, speculation aside, I'd say Occlusion's probably more likely. Or is it?
The argument, I think, against comparatively advanced tech, like clocks, is that we don't have any evidence. Except the Antikythera Mechanism and a bundle of weirdly accurate ancient maps, and a transnational megalithic culture capable impressive architectural/engineering feats.
Makes me wonder! But of course I'm no expert, give me a compass and who knows where we'd end up.
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