Brent,
My 2 cents worth...
If by tilt you meant the obliquity of the ecliptic, that doesn't affect
things.
Your question is about walking on a globe (3D), but I suspect you're
imagining it like a flat map (2D). A map (assuming the map is a Mercator
Projection) represents latitude as a straight line but when you move on
the surface of the Earth you're not really following a line that is
straight in 3D terms.
The line of latitude is a really a circle representing a sectional slice
through the globe. To compensate for unbending a circle in 3D to be a
straight line on a 2D map, something else has to get distorted: shape.
That's why on a map Greenland looks huge compared to other countries and
is so wide at the top. On a globe it looks smaller and more like a
rectangle than a very wide triangle. The extreme cases are the North and
South Poles which are points on a globe but on a map get stretched out
to be a line - they would take up the whole top or bottom edge of the map.
When you move on the surface of the Earth, following a true 3D straight
line would take you off into space. You can see that by placing the
middle of a ruler on the surface of a globe. The ends of the ruler are
not touching the globe, are they? If the point of contact is at a Pole,
then gradually tipping the end of the ruler down towards the globe's
surface will always make the point of contact follow a line of
longitude. If you start elsewhere on the globe and initially point your
ruler East, then rolling the point of contact will make it cross lines
of latitude as varying angles as you get closer to the equator.
Thus, to walk due East (i.e. perpendicular to a North-South line) on the
Earth, after each step you have to recalculate where East is and make a
minute adjustment in your direction. A magnetic compass does that for us
automatically; as well, maps show East-West as linear. The consequence
is that we're used to thinking that we're moving in a straight line, but
really we're turning slightly after each step.
Cheers,
Steve
On 15/09/2015 07:10, Brent wrote:
I'm confused maybe.
I live in the northern hemishpere and anticipating the equinox on the
23rd.
Supposedly the sun will rise due east.
So if due east is a right angle from north south and I traveled due
east I would not follow my line of latitude.
I would get further and further south of my latitude the further I
traveled.
So either the lines of latitude are not east west lines or due east is
not a straight line but curved.
I suspect lines of latitude are not east west lines?
They would work fine if the earth was not tilted, but it is.
Wouldn't it make sense to coordinate the globe so lines of latitude
(or call them something else) are straight and a right angle
from north south?
brent
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