I have blogged about time before, and was thinking about it again recently. This time (ha) about the abstractions we place upon it, and the effect of that (so one week is made up of seven days, for example).
I guess the whole point of these abstractions is that they were invented to make it easier to keep track of time and organise it. A day is fairly self explanatory, a unit of time between each time the sun rises; it is a fairly natural unit of time, just given a name to allow us humans to keep track of it. A month is roughly related to the phases of the moon, but a week is a bit weird - somewhere in between. Perhaps it something just divided well into collections of 7 days. Perhaps it is just random.
A year is the one that got me thinking. It has some rooting in nature (like the day) in that it is the time taken to go around the sun once, but it is still quite an abstraction.
We have all these different units to make things easier to understand, so you can think about things in smaller numbers as opposed to using large amounts of the smaller units.
Somewhat paradoxically, by doing this and abstracting away the larger amounts of time into smaller units, we can lose track of things, or think that the time between two points is less, depending on which level of abstraction we use - one year doesn't sound too long, 365 days sounds like a longer time, because it has got more numbers (I'm sure there is some human psychology behind this used in marketing). From this, time can pass quickly without us realising it (being busy with general life events is a distraction that helps with this). The bigger the abstractions, the faster it seems the time passes.
The very things we invented to keep track of time, can sometimes allow us to lose track of it.