Atomic clocks were First revealed in 1949, but by the mid 1960s they had progressed to the point where they had been the most accurate clocks on the planet; more precise than that which had become the master clock by which all other clocks and watches in the world was regulated up before then – the rotating earth itself. In reality, in comparison with the precise measured beat of the atomic clock, the ground was revealed to be rather a bad time-keeper. In 1967 one second of time was redefined as being 9,192,631,770 vibrations of this Caesium-133 atom, instead of one 86,400th region of the mean solar day.
In 1972, when atomic Clocks took over the function of the world’s master time-keepers, the time was initially set like any other clock to match the motion of the sun as it rose and set. Man’s most advanced technical triumph in keeping track of time has been constructed to agree with the humble sundial – certainly man’s oldest way of monitoring the passing of the day. Since then, atomic clock has become vital in regulating the increasingly intricate technology that creates the infrastructure of our lives. Internet web servers and email providers all need to operate in synchronized harmony. GPS satellites know the right time to within a billionth of a second so that they could keep us found to within a few yards of where we really are. Cell phone networks passing on our text messages and digitized voices also need to be aware of the opportunity to high precision.
But there’s a problem. The earth’s speed of rotation is gradually slowing down. The principal reason for this is that the moon. As the moon goes round the earth, it pulls at the waters of the great oceans of the world and moves them around, making the tides we see in ports and in the sea-shore. However, sloshing all that water around and dragging it on the sea bottom creates heat due to friction. The heat produced is finally radiated out into space, but the power to make that heat has to come from someplace. And that somewhere is the rotational energy of the ground the possible energy stored up in the planet by virtue of it rotating like a gyroscope. Another consequence of the tidal friction is the planet’s rotational energy is being moved to the moon’s orbital energy, so the moon is slowly getting further away from the ground. A hundred thousand years ago, back in the days of the dinosaurs, the afternoon was about 4 minutes shorter than it currently is. Ten thousand years ago, back in the days of Stone Age man, the day was about a quarter of a second shorter than it currently is. Back in 1967, the afternoon as marked out by the atomic clocks was 0.006 seconds shorter than it currently is.