I posed these questions last time:
Which two countries are these? Argentina and Australia.
Where do they touch? Yes, this is a trick question. Nothing touches Australia. However, both Australia and Argentina have claims on Antarctica. They touch at the South Pole. The Earth’s axis marks the common line that divides their respective air spaces (https://lnkd.in/gAnDGaw).
Why does it matter?
We call the South Pole 90° south latitude. But what if we called it “0”? If we called it “0,” then every point moving away from it would be positive. That’s because geography is never negative. If we started at the South Pole and walked one step into the Argentinian claim, we could say we moved into positive Argentinian space, but we wouldn’t say we were in negative Australian space. If we turned around, retraced our step onto the South Pole, and then took another step into the Australian claim, we would be in positive Australian space and not in any other.
This seemingly odd construct proves useful. Look at upcoming posts to see why.