What is Time?
Time is one of the most mysterious properties of our universe and 13.8 billion years ago, the clock was set.
It can whiz by or drag on, but time ticks ever onwards.
Time is the cosmic conductor, and nothing can escape its grasp.
Can we see time?
We cannot see time, or hear it, we cannot influence it in any way and yet every heartbeat, every choice and action, every inaction is a consequence of time’s continuous flow.
The passage of time creates change, and these are apparent everywhere. On a person, time is visible as human attributes such as beauty, speed and strength change over the years. In nature, sunrises and sunsets remind us of the passage of time on a daily basis.
The importance of the sun
The sun travelling across the sky formed the basic unit of time.
But a day is not actually a measure of time at all, it is a measure of motion. As our planet rotates on its axis, we move through space at 1,600 kilometers per hour. It takes 24 hours for Earth to do one full turn.
It is our planet’s steady spin that sets Earth’s master clock.
Days on other planets
This essential cycle that we often take for granted is however not universal. As soon as you leave our home planet, the 24-hour day no longer applies.
Mercury, for example, rotates at a snail’s pace, compared to us (1,408 hours in one day)! Venus is another example as it spins even slower! It takes longer to rotate on its axis than it does to orbit the sun, making Venus’s day longer than its year (5,832 hours in one day).
Each planet has its own unique day length. Mars has 25 hours in one day, Saturn has 11 and Neptune has 17.
Every planet in our universe spins at its own speed. Billions of worlds, each with its own clocks, ticking away to different rhythms, but all moving forward on a universal cosmic timeline.
Universal truth about time
On earth, whether you live it at high speed or in slow motion, all life must adhere to the same 24-hour day. And as the world keeps spinning, those days keep ticking by, dictating the lives of every living creature.
There is one universal truth about time: it has a direction. You can never go back in time, only forward into the future. This is time’s arrow, and it leaves scars on everything across earth and beyond. Scars differentiate the past from the present.
A time before time
13.8 billion years ago, there was a very big bang in our universe that created three-dimensional space and time. But space and time are not separate. Time is woven into the fabric of the universe, bound to space as our universe’s fourth dimension.
The Big Bang set the universe’s clock ticking, propelling everything into the future. It created the arrow of time.
From our universe’s very first moments, it pushes us all into the future, causing everything to grow, age and change. From childhood to adulthood, we all travel through life in the same direction.
The passage of time and stars
Early hominids noticed the passage of time with days and nights. The next thing they would have observed is the phases of the moon and the seasons. This was important for hunting and growing.
The seasons were particularly important for hunter-gatherers as it was vital to get a better understanding of the passage of time to forecast migrations of animals.
The measurement of the passage of time was also important to hominids growing crops.
The population of Egypt, for example, grew from nomads who settled along the fertile Nile banks and transformed Egypt into a sedentary, agricultural society by 4795 B.C. Farmers sowed and harvested crops during seasons around the flooding. Ancient Egyptians developed a method to measure the Nile’s flood level, as their harvests and livelihood depended on this.
For hominids living close to the sea, tides are important. Tides are caused by the magnetic pull of the moon and sun on the planet, and they occur in regular cycles that can be predicted.
Fish may concentrate during ebb tides. Fishermen follow the tides and learn to fish during levels of highest concentration to make more efficient use of their time.
Tides affect other aspects of oceanic life, including the reproductive activities of fish and ocean plants. Floating plants and animals ride the tidal currents between the breeding areas and deeper waters.
Early hominids were already monitoring stars 11’600 years ago – at least!
Göbekli Tepe, built in 9’600 B.C. is the oldest acknowledged monumental structure on Earth.
It is about 7’000 years older than Stonehenge and about 7’000 years older than the Giza Pyramids. Built at a time when Earth was just emerging from the last Ice Age.
Karahan Tepe is another example that was built at about the same time and is now referred to as the biggest archeological discovery of the 21st century. The builders were believed to have a deep understanding of astronomy and how time related to stars.
The importance of stars in religion
Temple of Mnajdra (Malta) is another example of a structure that was built by hominids that had an extraordinarily advanced understanding of the cosmos.
These hominids observed the rising of the sun and the position of certain stars. Mnajdra’s builders devised an ingenious way of tracking the heavens. On the spring and fall equinoxes, respectively 21st March and 21st September, the rays of the sun exactly bisect the temple entrance, flooding the deepest recesses of the inner shrine with light. On these occasions, the interior of the temple would have glowed and sprung magically to life! At sunrise on the summer and winter solstices, the longest and shortest days of the year, a different distinctive projection of light precisely illuminates the edges of the megaliths to the left and right of the doorway.
In fact, we see the importance of stars in many ancient constructions, such as in the Great Pyramid of Cholula in Mexico, Stonehenge in the UK and the Temple of Karnak in Egypt.
Stars, timekeeping and sailing
As humans developed navigation skills that enabled them to sail around the world, they needed to have points of reference that they could rely on and this is where stars were of great importance, especially when navigating at night. At the beginning of the 16th century, navigation brought about a great leap forward in terms of improvements in time-keeping devices.
The future of timekeeping
The race for improvements in time-keeping devices has only sped up since then and, in today’s world, the accurate measurement of time has become extremely important as most of the devices we use rely on a precise measurement of time. As we have seen the measurement of time started thousands of years ago, refined by different civilizations through the years, the decades, the centuries, and the millenniums.
Humans have been from a very early age on a mesmerizing horological journey and there is still so much to do to improve timekeeping! Especially when we think of humans travelling through space!
Human’s efforts in trying to accurately keep track of the passage of time still has a very bright and interesting future ahead!