I have the kind of mind that often wonders about the ‘why’s of some everyday things – things we normally just take for granted for most of our lives never considering, just accepting… until one day your 6 year old asks you something like… “Mom (Dad), What pulls me back down to the ground when i jump up high?” “Gravity” “What’s Gravity?” “Why doesn’t it make the birds fall down?”
For reasons i may explain in another post, recently i’ve been putting some thought into ‘degrees’.
Not the kind of degree that measures temperature – nor the kind smart folks get from Universities or dumb folks get from Russian internet sites for $15.
The ‘Other’ kind – one that is used to measure ‘angles’ (No Billy, not measures Angels – angles!) 🙂 Initially the kind that measures places of latitude or longitude on a map or globe that defines a place’s position.
‘Everyone’ knows the North Pole is a very cold place where Santa lives and works and writes his Naughty/Nice list and the South Pole is at the opposite end of the planet where penguins waddle, freezing their tootsies off and where ‘Summer’ is briefly held for a couple of days during the middle of Winter.
Both these places are located at the only point on the entire planet that is defined as being at 90 degrees latitude, one 90 North and one 90 South – the two Poles of Earth through which an imaginary line or axis of rotation passes. Every other place on the surface of the earth has a latitude measured at less than 90 degrees, which means if you take a line from the very centre of the earth and draw it out to the Equator (another imaginary line that circles the world around the middle – it’s waist) which is given as the ‘starting point’ for the measurement of degrees of latitude and so is set at zero, and then take another line from the centre of the earth that passes through the place you are at or measuring, those two lines form an angle of less than 90 degrees. (The four angles in a square, also called ‘right-angle’s)
To help picture this, take an object you are very familiar with – a watch, or a clock with two hands. At 12 pm the two hands are together and have an angle of 0 degrees (no angle) between them. At one oclock the hands have an angle of 30 degrees between them; at two oclock, 60 degrees and at 3 pm exactly 90 degrees. With a clock you can keep on going as the hour hand always moves in one direction away from the 12 at the top, increasing the size of the angle from 90 degrees all the way to six oclock when the hands form a straight line and the angle (measured through the centre of the clock) is 180 degrees. Then, depending on your mood or perspective, you either change the side you measure the angle of the hands through and ‘shrink’ the angle back through 90 degrees back to zero, or, you can keep measuring from the same place (the centre up to the 12 then back to the centre and the hour hand) and get answers of up to 360 degrees between the hands when they come ‘full circle’ and are together again at 12 am. A ‘full’ circle has 360 degrees. Skaters, skiiers, boarders and BMX/motorcycle stunt riders do stunts referred to as 360’s or multiples of a full circle or one complete rotation.
So what is there to consider about these degrees you may be wondering? (if you are still reading without your eye’s glazing over by now).
Well, it’s this: we only have up to 90 degrees North or South – when we get to 90 degrees we can’t go any further! If we keep moving in the same direction we don’t get to 100 or 110 degrees but we move back down through 89, 88,.. 80, 70 degrees latitude, etc.
So why don’t we do that with the degrees of longitude East or West??
Why is there no East and West ‘pole’??
“Well,….” you answer, “the earth does not rotate through an East/West pole axis like it does through the N/S poles!”
And you’d be quite right to say so.
But if you think about it – that makes NO sense whatsoever.
Because, no-one can actually locate either a north pole or a south pole (if someone had not previously done some seriously heavy mathematical work combined with surveying and actually built a marker at the South Pole. You can’t build one at the North Pole because it is below a floating ice sheet that ‘moves’ (and lately even melts) at different times of the year!).
The North and South poles are far more of a ‘theoretical’ place that is only ever seen on a picture of a map or seen on a model of the globe for almost all of us, whereas all of us are able to ‘see’ a point both East and West every day we can ‘define’ as a ‘pole’ which is marked by the rising and setting of the sun. It is far harder to locate a North or South Pole direction for any place that you don’t already have a map for. (Spend a whole day and night outside and try pointing to where the North or South pole lies without any other aid but what you see with your eyes and see how well you go!)
Those of us who actually pay these events any attention know that there is a very slight change in these positions of sunrise and sunset each day for 182 days or so, from mid-winter to mid-summer (they move from South to North, for those in the ‘Northern’ hemisphere, before reversing back over the rest of the year), but this is ‘negligible’ on a daily basis and would not prevent their use as locating the direction of an East or West ‘Pole’ for a particular place on the globe that does not vary for that place on any given day.
So just why is it that we have up to 180 degrees East or West of the imaginary line called the Prime Meridian (that passes through London and Paris as well as parts of North Africa, South Atlantic Ocean, The South Pole, large parts of the Pacific Ocean and back through the North Pole to London again) and not just 90 degrees like we do when moving North or South of The Equator?
Especially when both are measurements around the surface of a sphere (Earth) – which is almost perfectly symmetrical North and South and East and West?
Why is it if you walk along the line of zero degrees longitude from the equator to a pole (or swim cos a lot of it is over water!), when you finally pass through the Pole you instantly change from zero degrees longitude to 180 degrees??
(At this point i’d just like to point out a weird fact: if you stand at the North Pole then try to move in ANY direction, whichever direction you take, you will be heading due South – you can’t move in any other direction from the North pole BUT ‘South’; same as you can’t move in any other direction than North at the South Pole! If you start to move one way then turn 90 or even 180 degrees from the first way you were facing you are still heading in the ‘same’ direction! Once you’ve taken your first step then you are able to move north, south, east, or west again but for your first step it can only ever be in the one direction ‘opposite’ to the pole at which you are standing.
So, we can only move through 90 degrees around a globe north or south but we can move through 180 degrees east to west?
Does that not seem strange?? They are, in effect, the same measure; one degree of angle measured through the centre of the earth; measuring (for all intents and porpoises) 🙂 a symmetrical round ball.
So why can’t they both stop at 90 degrees if one does?
Well, rather weirdly, i think, if we DID have an East and West Pole on our globe like we have the North and South ones and only measured up to 90 degrees away from a zero degree line before moving back around the ‘other side’ of the world back down to zero.. every place on the globe would have a ‘twin’ location with another place, each having exactly the same co-ordinates! (With the exception of the now ‘four’ Poles).
You could not navigate from one location to another, defined by their N/S and E/W degrees of latitude/longitude, without becoming confused as to exactly which location of two ‘equal but different’ ones you were starting from and going to!
Hard as it might seem to make sense out of, our degrees of Latitude (which are like flat slices cut through an apple or round melon) make ever decreasing circles around the surface of the planet starting at it’s widest distance around the equator and becoming ever smaller the closer you get to a Pole (90 degrees) where they effectively become just a single point on the ground with no diameter at all!
Whereas our degrees of longitude (which, remember, are the ‘same’ degrees) all make a circle of the same size (one the circumference of the Earth) but which ‘rotate’ through and around the earth’s North-South axis.
At the Equator an angle of one degree either North, South, East or West is covered by traveling about 67 miles in a straight line along the surface of our planet.
This remains the case as long as you move in an East-West direction (latitude) for as far as you can move until you eventually end up back where you started.
However, the further you are away from the Equator, degrees of longitude get ‘smaller and smaller’! At a latitude of 45 degrees (Portland, Oregon; N/S Dakota border; Middle of Maine; Switzerland) one degree of longitude ‘shrinks’ from 67 miles to a mere 45 miles or so!
If you were 67 miles from one pole you would be one degree away in latitude but the same mileage in an East-West direction would cover over 60 degrees of longitude!? ( That is more degrees than there are between the US East and West coasts!)
One final bit of weirdness caused by our system of selectively choosing different ways of measuring degrees West to East versus North to South…
If you walk out of your door and head due south for one mile, then turn 90 degrees and head due west for a mile then turn another 90 degrees and head due North for one mile you would have covered a ‘U’ shape and would be a mile from (West of) your home. But if you moved your house so your front door was right at the North Pole and tried that… you’d be exactly back at your front door again! You would have walked in a triangle – with two (three) angles of 90 degrees each!
So – that’s just a little more of how my brain works.
Anyone remember the Wizard of Oz? and the Scarecrow?
I’d be quite happy to change places with him before he got his brain – sometimes!