Hi Chris;
I did what you said with my globe and saw what I expected.
So I am not sure I understand what you are saying.
When I look east along my latitude on the globe it is not a
straight line from my perspective on the surface of the
earth it curves to the left, north.
So if my line of latitude is on a East-West line, it is
curved. So east is not a straight line when I point east
using a compass, it is curved also.
If you look at this map you can see the curve:
http://upload.wikimedia.org/wikipedia/commons/thumb/5/56/World_map_longlat.svg/300px-World_map_longlat.svg.png
Dick Koolish thinks I am looking along a great circle when
looking east and not a latitude circle. That would be a
straight line but that doesn't sound right to me.
North-south follow longitude lines and east-west are at
right angles to those. A great circle at my location would
not be a right angle to the longitude. Maybe that only works
at the equator?
So if my latitude line is curved from my perspective, the
direction east is curved also.
I just realized that when I hold my globe straight, with no
tilt to the axis, east and west, north and south make
perfect sense and east is not a curved line at all, it is
straight. The earth isn't actually tilted like we see on a
globe, that tilt is just to show the position of the earth
in relation to the sun.
I can sleep tonight, east is east and a straight line like I
always thought it was.
But then again...
brent
On 4/17/2011 4:41 PM, Chris Lusby Taylor wrote:
Hi Brent,
Everywhere in the world, the sun rises due East on the equinoxes (March 20th
and September 23rd approximately).
Everywhere in the world, the sun rises in the North East between those
dates, such as today. (Ignoring the polar regions.)
May I suggest you get hold of a globe, stick pins in it, or perhaps stick
tiny paper sundials on it at your location and several points due north and
south of you. Then, in sunshine, turn the globe until it is evidently
showing sunrise at one or more of these locations, and the north pole is not
in shadow (so it is summer in the northern hemisphere). See for yourself
the direction on the globe of the shadow when the sun is anywhere north of
the globe's equatorial plane.
Also, on the globe look at your line of latitude, 35North. Can you see that
it is actually a circle parallel to the equator? This circle defines a plane
parallel to the equatorial plane (let's call it the latitude plane) and only
a few thousand miles away from it.
So, given how small the earth is, compared with the distance to the sun, if
the sun's rays at the equator are coming from north of the equatorial plane,
at 35N they will be coming from north of the latitude plane.
Only if the sun were very small and very close indeed to the earth would it
appear south of east to someone at 35N, while north of east to someone on
the equator.
Your line of latitude does, as you believe, go due east-west.
I hope this helps
Chris
----- Original Message -----
From: "Brent"<[email protected]>
To: "Sundial List"<[email protected]>
Sent: Sunday, April 17, 2011 9:02 PM
Subject: Looking east
Hello again;
I live at 35N latitude.
I notice the sun is rising (in April)to my North East.
That didn't seem right because the sun never gets further
north than the Tropic of Cancer around 24N.
The sunrise might look this way because of the spherical
shape of the earth.
So it started me thinking about where is east.
When I look east I am looking along my line of latitude.
And that line is supposed to be straight.
But I now think my line of latitude as well as "east" makes
a big hook to the left as I look easterly and is not
straight at all from my perspective.
Am I confused?
thanks;
brent
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