Hi Crunchie. Time is periodically updated – the current time we keep is referenced to the rotation of the earth, and regularly updated by leap seconds and so forth to keep it exact. So the first time setting is pretty arbitrary. The egyptians used different types of sun-clocks including obelisks. As to how it was set – midday is when the sun is highest in the sky. Count forwards and backwards from there.
Helllllloooo crunchiejelly! I am still wondering what exactly crunchiejelly is, maybe you can explain it sometime? Does it have berries or something??
As far as the first time, I am thinking you could mean one of two things. The origin of time, or the first time we started keeping track of time. The current theory of the origin of time is that it originated with the origin of space (i.e. spacetime!) when the universe was created in the Big Bang.
As far as when did humans first start keeping track of time, as in “setting time”. Well I don’t think that is exactly known. The ancient Mayans had a amazing accurate calendars. I think they were one of the first peoples to really keep close track of the stars and use them to make highly precise calendars. The Egyptians are another good example, thanks to Drew! So we’ve been keeping track of time since ancient civilizations but it is unknown exactly when we started doing this. The calendar has been reset many times over the ages. In particular, some civilizations such as Europe through the middle ages did not have super accurate calendars – sometimes they would have to adjust by days, or even weeks, to get their calendar back on track again! Can you imagine loosing a whole month for such a silly reason? Nowadays we make sure that kind of thing doesn’t happen by using time standards (http://en.wikipedia.org/wiki/Time_standard) like the Earth’s rotation!