It's about time.

I've been thinking about time. Not in the Einsteinian sense, but in the human sense, the wristwatch sense.

What is it for, why do we use it?

The answer is fairly straightforward. Time of day is a tool. We use it to coordinate with the world, physical and social. In other words, to help us do things at the right time either in relation to the sun, moon, tides etc, or in relation to other people. And the tool we use for a given task changes over time, depending on the way we live our lives and relate to the world and each other.

Once upon a time (no pun intended), we all lived our daily lives according to the sun. Time related to sunrise, noon and sunset and these depended on where you were on the planet. We were in touch with our environment. Society and technology developed. Division of labour meant that not everyone was ploughing a furrow or herding sheep and so not everyone was so closely wedded to the sun. As our working lives (and it was mostly work) became less wedded to daylight, so did our measurement of time. We went from using sundials to clockwork. Of course we still set our clocks locally, using the sun as reference. Consequently, noon in Bristol happened about 10 minutes after noon in London. It was only with the combination of of really accurate timepieces, the coming of the railways and the telegraph that time was standardised across a country in the 1840s and 50s, using what was called Railway Time.

During the mid 19th Century, local solar time persisted and some clocks displayed both the local time and GMT, which did not become the official legally recognised time until 1880. The idea of using more than one time was not uncommon in this period. World trade, communication and transport demanded mutually comprehensible time references. This could be achieved either by knowing what time zone you were referring to and doing the maths, or by reference to a universal standard time. Italian mathematician Quirico Filopanti proposed such a universal time to be used alongside local time zones for astronomy and telegraphy. Such a universal time would provide a point of reference for global events and make it impossible for an event to end before it's begun simply by crossing the international dateline. In the 19th Century, globalisation had not yet proceeded to the point where it was really useful and the technology was probably not refined enough to keep everyone on track. It's worth noting that India and China, both vast countries crossing several time zones, only use a single centralised time.

Now, we have the internet, global positioning, vast processing power and friends and business partners all around the world. Many of us work from home at least some of the time and  may never meet the people we do business with. So in a world in which universal time is relevant and possible, what of local time? Here's the really interesting part. Local time can now be liberated from the time zone, artificially shackling it to its capital city. Micro time zones, kept pace of by the device in your pocket, on your Google Glasses or in a chip in your head; can allow you to live much more in tune with your neighbours and your world. Don't worry about how you'll work things out. Your gadget will do the work. All you need to know is that you want to meet your friend in Brighton at 1400. If that means 1408 where you're travelling from and 1356 where she's coming from, that's no problem. Your journey time, transport connections and everything else will be taken care of.

Why, seems the obvious question. Universal time has a fairly obvious practical use. The year 2014 will only have one start - a shame for those who can only imagine fireworks as the way to herald the exact start of the new year but hardly a deal breaker. Coordinating global communication will be easier. And referencing events of global significance will be clearer. As for the local times, the answer is that given our information technology capability, they are the flipside of universal time. Zones shackled to 19th Century industrial nation states are irrelevant in a global society, but noon where you are retains a meaning. Children can walk to school at the most practical and safe time all year round, across the country. No need for the sudden loss of an hour's daylight in the autumn.

The most important thing to remember here is that the hours on our watches are human inventions and we already work with numerous definitions of time in parallel - based on the sun, the stars, the day, the year or caesium 133. Are measurement and use of time has changed in the past and it is likely to again. The capability to measure time and place accurately and the need to coordinate globally mean that change is likely again.