I’m watching Prometheus having a few casual perlenbachers (thanks lidl) and the geologist guy just heard there was a life ‘ping’ one click west of them.
Just so we are on the same page, the movie is set on a moon of a planet about two years travel distance away from earth in 2089.
The geologist reacted badly to hearing about this potential life source (I like rocks, that’s all I like) and said ‘let’s go east’, to avoid the unknown danger of the unknown.
Then you thought. East. East as in on a map, with north at the top you move towards the right of the page.
But how the hell did these people agree on what east was on this new moon planet?
On earth north is at the top of (most) maps, and we decided this based on the fact that the sun moves across the sky east to west, so we’d better keep one of the other two fairly constant. It doesn’t hurt that we developed the compass (thank you ferro-magnetic earth core) to help abstractly identify north.
But on this new planet moon, how do they assign west? What if they were upside down when arriving, and left is actually east? What if they have a rotation that isn’t effectively coplanar with the orbit of their sun? What if they can’t agree upon which way is left?
Which makes me think, how did we decide to draw maps ‘facing’ up? If I got my map of Ireland, or limerick ( both of which I took off my wall yesterday whilst moving out of my student accommodation) and turned it upsidedown would it not still show me how to get to the crescent shopping centre? The shape hasn’t changed, only my reference system to it.
Or how about the map of San Diego I am about to form in my mind this coming summer? What if I wanted to ‘learn’ it upsidedown, with a west rising sun, and a south facing map? I could do it, I just couldn’t refer to any other maps written in ‘north’.