54. IT’S ALL RELATIVE

The lady in this photograph appears to be losing her balance, but is she? Why do we think this might be the case? What if the ‘horizontal’ and ‘vertical’ edges of the background wall were skewed?

This is in fact what is happening here. This set-up occurs in Puzzling Park, an interesting stop off in Wanaka in the South Island ofNew Zealand. The room is constructed at an angle, and even being here can be quite unsettling.

There are many situations in life where a position or measurement is relative to some base. We might think of temperature measured relative to a zero point. Or the position of a point with coordinates relative to given origin and axes. Or sitting in a railway carriage and watching the adjacent train moving off – am I moving or not? Think of some further situations. This idea is fundamental to Einstein’s ‘Theory of relativity’.

http://en.wikipedia.org/wiki/
Introduction_to_general_relativity

    

– Paul Scott