How much time do you have to make the observations? "It's the statue, man, The Statue."
Galileo also proposed used the positions of Jupiter's moons as a very distant clock.
For obvious reasons, neither of these ideas was as useful as having an accurate timekeeper.
There's a good overview here.
http://www.crichtonmiller.com/longitude.htm
I don't have the tech. knowledge to know whether this guy is making things up or telling the truth, but I've been linking to his info. He is claiming that there was, indeed, a simple way of measuring both latitude and longitude using a device based on the celtic cross.
Is he crazy? Is it nonsense? Certainly he is claiming that this was used thousands of years into the past. I'm very interested in reading a tech person's view(s) of this guys tech. theories.
What I mean by that is: he has a lot of other theories too, but...does his device work? Don't fight forces, use them R. Buckminster Fuller.
Here is what I understand, tell me where I go wrong.
[edit]
How to mark a standard time reference before Greenwich and clocks? What could be the same for all, yet different at different longitudes?
Well...nothing. There has to be a reference point. So, how about where you live?
Ceebs! My mind is blown again!
Look at draco (but you know all this! Humour me!) There it lies, at the centre of the ecliptic pole. The true centre...is dark. No star.
Well...
Maybe not....
The ecliptic pole. I needed that. Our celestial pole is at the bottom of Ursa Minor, the last star. Polaris. In the time of the Egyptians (have I understood this correctly?) our north pole pointed more or less directly at the third star in Draco's tail.
http://www.pakhomov.com/duat.html
The galactic equator...
Another wheel!
It's like taking mushrooms, but it isn't. How about learning all this, and then taking mushrooms?
Whoooosh!
Celestial north, south, east, west
(indulge me!_
Ecliptic north, south, east, west.
Galactic north, south, east, west.
The moon.
The planets.
Add psilocybin, a hill, a clear sky, no unwanted earth-light, warmth, soft grass, like back...
VOOOOM!
And the report back?
Hyperbolic trajectories!
http://ourworld.compuserve.com/homepages/dp5/dust2.htm
Ach...I ramble.
...so...recapping. Longitude is time from somewhere. You look up. There is Draco. It marks out the spot above the sun. There is the moon. It measures time against the sun (in degrees--and therefore in minutes and seconds?) There are the stars. We don't point to the ecliptic pole. We point to the celestial pole. Polaris. This difference is enough, if measured accurately, to work out where we are on the planet...because...
we know where the moon should be, relative to the stars. And at two different points on the globe, the difference: moon, pole star, draco = movement?
The only way to navigate by the moon is to work out the angular differential from a star over time and motion with the help of an almanac reference This requires tracking the moon along the ecliptic and using certain stars in known constellations that the Egyptians called a decan of which there were 36 in one complete Zodiac to make up 360 degrees. But that knowledge is insufficient on its own, there is a crucial requirement, an instrument of sufficient accuracy The moon tracks over the earth at 720 nautical miles per hour and moves against the zodiac (a great circle) 30 arc minutes in 60 minutes of time during which the position of the observer has spun through 900 nautical miles on a great circle. To find a longitude position by measuring the angular difference requires an accuracy of observation of at least 1 arc minute to achieve a longitude accuracy of 15 nautical miles at the equator reducing in proportion by latitude.
So the questions are:
1) Could humans many years ago have worked this out?
My answer: yes. They had the sky. They had time. They had brains like ours. Earth--axis. Sun--axis. Moon--relationship.
???
Did humans long long ago--thousands of years, counting 2,3,4, and beyond...beyond even the disappearance of..the ice...
http://en.wikipedia.org/wiki/Ice_age#Recent_glacial_and_interglacial_phases
...did they know this more than 10,000 years ago? I can't see why not. (It's taken me about a week to start getting my head around it.)
2) Did they have the mechanical means to use this information for longitudinal navigation? Did they have a sense of lateral time? -- I am here now, and you are there now, but where you are, it is a different time...of day and, if you are in New Zealand, year. But it is still Now.
So...now where am I?
Did they have measuring devices for that? Which would have been useful to understand where on earth they were, relative to their home. And I'm assuming everyone knew the earth was a globe. (Well, I'm assuming those who had worked out the relationship of the celestial pole to the ecliptic pole knew the earth was a globe.)
The galactic equator! The galactic north pole!
As I understand it, the argument comes down to: did they use snakeskin as an exponential device in order to calculate longitudinal movement? Why would they need it? Because they sailed across seas, I assume. A nagivator's riddle. Where am I? Where am I going? How far am I from where I started?
http://www.crichtonmiller.com/sophia.htm
Crazy theories!
But I learned about longitude, and the celestial equator, and...yes! The ecliptic north pole!
Ah, the power of the internet...I ramble to this screen and get to see...the universe in pictures.
Cough cough! Don't fight forces, use them R. Buckminster Fuller.
I'm assuming everyone knew the earth was a globe.
There is no evidence for anyone at the time of Columbus thinking the world was flat. in fact the flat earth story was the invention of Washington Irvine,
The ancient Greek and Egyptians new that the world was round and calculated its size correct to within 1% and 5% respectively, and considering that they used people who paced out the distance between Thebes and Cairo as a basline for the calculations that wasn't bad.
The timepeice is still the difficult step in calculating longitude, without complicated calculations. although if you wish to take on these calculations there is evidence of a variety of observatories in India, china and (I think)Iran. to work out the difference, you would have needed to combine the observations at these several sites to work out what was happening.
could they have done it thousands of years ago? that's hard to say, If you ask an Archaeologist, youll just get the answer of it being "Ritual" which is their get out line when they don't want to say "We don't know". Any idiot can face a crisis - it's day to day living that wears you out.
So...
...the snakeskin is needed for the accuracy somehow...maybe to pinpoint and then to read off? Because snakeskin was a finer measure (the tip of the scale--yet still visible to the human eye--than any manmade mark--at the reading end, not just for the tangential?
(I think he's in wild speculation with the snakeskin...but I enjoy wild speculation!) Don't fight forces, use them R. Buckminster Fuller.
to even know that one can determine longitude through the apparent position of the moon against the fixed stars, one would have to have compiled accurate almanacs at two widely separated locations, and then compared them. "It's the statue, man, The Statue."
4)5) Regarding how accurate, much more accurate than 61 arc seconds. That's about twice the Moon's apparent diameter, and the distance the Moon travels in the sky in 111 minutes! If we go from time to latitude, it is not nice at all.
Migeru wrote about measurement precision, e.g. you want to measure the position of the center of the moon, but you have a luminous object just below 30 arc seconds in diameter.
To emphasize what gave me for thinking about the snakeskin, it wasn't simply its use, but this:
The skin of a snake is exponential
I'm not sure what's exponential about it BTW, I tipped that the scales get bigger away from the head or something. *Lunatic*, n. One whose delusions are out of fashion.
DoDo, I don't follow myself either!
Backing way up: all I (mis?)understand is:
It's possible (using specific events such as eclipses) to bring exactitude to our study of the earth-sun-moon-stars relationships. We can measure different combinations, so I'm assuming that ancient peoples could in theory have known how to calculate movement west-east/east-west.
(And as Migeru said: why would they think there'd be any difference, unless they had travelled east-west/west-east, taking their almanacs, far enough to discover the differences--or else they met people from somewhere else who had almanacs...which didn't match? I like this idea because either
a) two different groups came to the same conclusions re: rotation, position, etc...
or
b) the various groups were, in fact, connected--just maybe not at the speeds we imagine; maybe they communicated once a year or even less? I have no idea. I just like the concept.)
I can imagine that people who knew of other locations could work out their longitude relative to those other locations (did I read somewhere that the pyramids were an ancient equivalent of Greenwich? Zero = the north south line between a pair of pyramids or somesuch.)
Then I can imagine someone attempting to do this on a boat--no success. Maybe they would try different techniques, different devices. This guy's device...has he tested it at sea? Certainly it seems that holding something out at arms length while one gently or not so gently bobs up and down does not sound right. So then my question about minimum useful measurements. You're saying that the minimum feasible is the width of two moons, which is a useless measurement?
When it comes to degrees I get lost.
(I thought latitude wasn't a problem--you measure a star's height against the horizon or somesuch...I could well be wrong...I really am out of my depth at this point.)
With the snakeskin, I think he wanted his theory to match up to...all the signs. I suppose it's possible to e-mail him and ask what he meant.
And...bowing humbly...
I thank you again! Don't fight forces, use them R. Buckminster Fuller.
Certainly God doesn't like the idea that people once upon a time were sharing knowledge:
11:6 Yahweh said, "Behold, they are one people, and they have all one language; and this is what they begin to do. Now nothing will be withheld from them, which they intend to do.
11:7 Come, let's go down, and there confuse their language, that they may not understand one another's speech."
11:8 So Yahweh scattered them abroad from there on the surface of all the earth. They stopped building the city.
11:9 Therefore the name of it was called Babel, because Yahweh confused the language of all the earth, there. From there, Yahweh scattered them abroad on the surface of all the earth.
http://www.awitness.org/biblehtm/ge/ge11.htm
These are old pre-flood/post-flood myths, seen through the eyes of the Torah; I prefer myths that involve some happy humans somewhere communicating and getting along. The stars...seem a useful, because obvious, point , which might be the same myth seen a different way (except for the God confusing everyone part.) Certainly we have myths of before/after and the only cataclysmic before/after we have is the ending of the last ice age, which would confound all old social relationships...unless one were free from the effects--isolated. Yet it seems that all communities have flood myths; which would make sense if there were a global connection network pre-melt...
...contact between disparate groups. You mentioned that to understand the concept of longitude (or maybe I misunderstood!), one would have to have an almanac and then travel with it.
I don't know how far you'd have to travel west-east/east-west before the naked eye and memory pointed out that things had changed. Maybe never? See how little I know! In my imagination I see a person far from home, staring up at the sky as the moon goes past and thinking, "Hold on. That shouldn't be there, it should be over there." His friend from the other faf-flung tribe pats his knee. "Happened to me first time I came to where you live. Here, have one of these. It'll help," he adds, handing him a large mushroom...
*:R Don't fight forces, use them R. Buckminster Fuller.
I now get what you mean with the eclypses, e.g. that the ancients could have been aware of the Moon's parallax and put that in almanachs. This is the case at least with the Greeks -- Hipparchos is credited with the measurement of the Moon's parallax using a soler eclypse (probably 129 BC).
But for a navigator to get the parallax at an unknown location, that's another thing. So if, say, we want to get the error under just 3' for the Moon anywhere in the sky, the guessed location must be precise by 320 kilometres, while the error of the final result will be around half of that or more -- not very efficient. *Lunatic*, n. One whose delusions are out of fashion.
it's the difference between landing at Standstead--miles from London! Where to stay?
and landing in a country where they know of you and welcome you; and if you arrived a hundred miles (or whatever measurement you choose)...away from where you were heading...there wasn't a problem.
So I think the problem must have been aiming at small islands. They are the things you can miss.
If it was a problem; and if they didn't have alternative navigational methods as adjuncts to--or even alternatives to--the sky.
If you ask the following question:
"That's north, that's south, that's east, that's west" pointing, "Are we moving? And if we are, which way are we moving?"
If they look confused, you say, "The sun rises in the east and," drawing an arc, "it sets in the west. Which way are we moving?"
I asked a colleague today.
"Clockwise," she said. "I suppose we're moving clockwise."
But, for an hour or so she was as fascinated as me by the basic movements of planet (spin), sun (axis), moon (moooovement), and stars (tick tock)....
What was the measure of efficiency before those huge ice-sheets melted? Because humans have been around for long before they melted. I'm beginning to think...hmmm...who wouldn't have been inundated? Who would'nt have had their life revolutionised. Maybe some people in India, in China, the himalayas must have changed; but maybe they changed, and the inhabitants could change with the himlayas, which are still growing...
Bhutan has an "Annual Happiness Index"...or somesuch. Was it Laurent who pointed out the ridiculousness of GDP? It's ridiculous. An overthrow, and overhang, of Empire. "It's over there, grab it!"
The sun is our source of life. If we harness the sun's powers...we still live on an unstable ball of energy, with fruity effects--us!
So risk is ever present. But now people have no sense of solar risk, or lunar risk, or stella risk. All the risks are human-created. War. Famine. Destitution.
DoDo!
You got me rambling!
Thanks for all your input. Very much appreciated! Don't fight forces, use them R. Buckminster Fuller.
And you got me thinking! Thinking about a hypothesis I would normally have dismissed out of hand (due to its bad wording). Soon I'll post a second summary as top-level comment. *Lunatic*, n. One whose delusions are out of fashion.
If you're at the same latitude on the same night, there should be no parallax. "It's the statue, man, The Statue."
15 degrees of latitude is one hour of difference in local time, during which the moon will move by 33 arc minutes (about one Moon apparent diameter). So that's the kind of accuracy we're talking about. "It's the statue, man, The Statue."
An instrument capable of sidereal measurement to 1 arc minute would result in an accuracy of 7.5 nautical miles at 45ºN
It is one thing to determine the distance between two (pointlike) starts to 1 arc minute by naked eye (with the aid of his instrument) but quite another to locate the moon to that accuracy. "It's the statue, man, The Statue."
