- #1

Adyssa

- 203

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**What is the relative difference in the distance from the sun of two points on the earth. Specifically Montreal, Canada and Melbourne, Australia.**

I started by finding out their respective latitudes. With these in hand, I drew a circle and some interior right triangles and set about finding the horizontal distance component from the equator to the point on the circle. I'm pretty sure I have these correct, here is my data so far:

Radius of Earth: 6378.1km

Montreal:

-Latitude: 45.5081° N

-Horizontal distance from equator: 1908.3km

Melbourne:

-Latitude: 37.7833° S

-Horizontal distance from equator: 1337.3km

Now, I need to account for the axial tilt of the earth, which is 23°. Given that it's the middle of summer/winter, the difference in distance from the sun will be at a maximum. What I did was to get the horizontal distance component for a point (the equator) at 23° latitude, which is 507km, and +/- from my above results, and I get a relative difference in distance of 1585km between the two cities.

Anyone care to comment or correct my reasoning? :)

Also, what is a good resource for astronomical measurements? I'd like to turn this into a program but I need to know about the elliptical orbit of the earth.