A history of time
Some several billion years after the big bang, humans came along and began measuring time, at first with sticks, shadows and sunlight and eventually through to the watches on our wrists today. But how did we get from sundials to atomic clocks? Alexi Baker from Cambridge University told Kat Arney about when we began time keeping...
Alexi - Well, it's the most basic level, it's probably gone back hundreds of thousands of years because of course, humans were perceiving sunrise and sunset, the changing of the seasons. But at least in more recent millennia, also things like the equinoxes and the solstices, and the movement of bright stars and planets like Mars and Venus. But in terms of building implements - tools - to measure time, that's gone back at least 4,000 if not, more thousand years.
Kat - So, what do we know about the very first ways that humans started to actually measure time and what sort of divisions of time were they trying to keep track of?
Alexi - At the most basic level, there could be the measured burning of incense or candles, materials like that and we also see ancient monuments and buildings align to cyclical astronomical events, things like that. But in terms of what we think of as timekeepers, it was really sundials, water clocks, and hourglasses which were the earliest appearances.
Kat - When do we start to see the first sundials and these water clocks? What's going on there?
Alexi - It's mostly within the past 3,000 years in places like ancient Egypt or Mesopotamia, China, and the ancient Arabic world.
Kat - What's a water clock? Tell me about this. How did that work?
Alexi - Well, the water clock, at its most basic form is just the measured pouring of water from one vessel into another. But they could be made a lot more complicated. Even in ancient Greece and ancient Egypt, they were already starting to add gears and the escapements and things we associate with modern technology.
Kat - When did people start feeling this need to measure time so precisely rather than just going, "Suns up. Let's go out and do a bit of farming"?
Alexi - Initially, it was because of activities like astronomical observing and navigation because of the association of longitude and time. But the time when it really became widespread across society was the 19th century because of the advent of the railroads and steam power, and electricity and mass production, and things like that.
Kat - So trains certainly not waiting for your sundial to roughly tell you.
Alexi - No.
Kat - Kind of the train is going now-ish.
Alexi - It was also the first time that they wanted to keep. They wanted to synchronise time across large geographical areas. That was a new sort of development.
Kat - And how then did we see these clocks starting to change and moving towards for example, the kind of clocks we have today?
Alexi - Well, in terms of society at large, it really wasn't until the 1800s that it starts to move towards our modern clocks because until then most people couldn't even afford any sort of timekeeper except for like an hourglass. So, in the 1800s, you start to get more mass production and more activities such as factory work and steam powered, and electrical work, and the spread of the railroads demanding more precise time. So, that's really when timekeepers spread across society and also start becoming more precise from our perspective.