"The views of space and time which I wish to lay before you have sprung from the soil of experimental physics, and therein lies their strength. They are radical. Henceforth space by itself, and time by itself, are doomed to fade away into mere shadows, and only a kind of union of the two will preserve an independent reality."
Hermann Minkowski, 01809

Time and Space
In the previous post I surmised that current temporal standards offer poor support for historical data. I also know that modelling time at deep timescales is going to throw up some new problems. The thing is, once you start messing around with time outside of historical systems like calendars you run into another dirty little secret. Time and space are related. We've known this for over a hundred years but temporal specs are all geared towards events in the short now, so fiddly little problems like relativity are conveniently ignored.

Even if I ignored relativity, I can't ignore space. Recent temporal innovations like daylight saving time and the timezone system are all local modifiers based on spatial coordinates. What I find odd is that I haven't encountered a single specification that tries to treats time and space equally.

Hermann Minkowski
The German mathematician Hermann Minkowski (1869 - 1909) was the first to formalise the notion that space and time are not separate. He proposed that the best way to understand Einstein's special theory of relativity was to use a 4 dimensional space he called spacetime. It's often referred to as Minkowski spacetime to differentiate it from a slew of other modern multi-dimensional theories.

Getting your head around the ideas of relativity and spacetime isn't as hard as you might expect. I found some great articles here that walk you through all the concepts using simple examples. Getting my head around the mathematics of spacetime is another thing entirely!