Answering Common Questions About Time Itself

Elizabeth Tower and Big Ben circa 1897 / Credit: NBC

What Is the Simple Definition of Time?

The measured or measurable period during which an action, process, or condition exists or continues: duration. A non-spatial continuum that is measured in terms of events which succeed one another from past through present to future. It is the thing that is measured as seconds, minutes, hours, days etc.

So, time is the progression of events from the past into the future. It can only move in one direction, forward, and cannot move backwards. Although, it is still unknown why time cannot move backwards in the natural world.

How Do You Explain Time?

Physicists define time as the progression of events from the past to the present into the future. Basically, if a system is unchanging, it is timeless. Time can be considered the fourth dimension of reality, used to describe events in three-dimensional space. It is not something we can see, touch, or taste, but we can measure its passage.

So, to accurately describe time, you can look to a few answers: one in physics and philosophy (time as a physical phenomenon), another in psychology (our sense of passing time), the third in mathematics and engineering (the time that we measure and use to regulate our lives), but the system of measuring it is relatively consistent.

Is Time an Illusion?

In Albert Einstein’s theory of relativity, time is woven together with the three dimensions of space, forming a bendy, four-dimensional space-time continuum – a ‘block universe’.

Einstein’s equations portray everything in the block universe as decided from the beginning, the initial conditions determine what comes later, and surprises do not occur, they only seem to. This predetermined view of reality remains popular today, as it is predicted by general relativity.

However, people who are studying time in the modern world point to troubles associated with this line of thinking as evidenced in quantum mechanics. At the quantum level, a particle maintains simultaneous quantum states until you measure it, at which the particle will adopt one of those states. The mysterious thing about this is that individual measurement outcomes are random and unpredictable, even as particle behaviour collectively follows statistical patterns.

So, this inconsistency between the nature of time in quantum mechanics, and the way it functions in relativity, has raised uncertainty and confusion. It is the divide between the determinism of general relativity and inherent randomness at the quantum scale.

We observe reality as a sequence of events and assign a concept of time to it based on our observation. This states that space and time are part of a four-dimensional structure where everything that has happened has its own coordinates in spacetime.

An excerpt by physicist Max Tegmark:

"We can portray our reality as either a three-dimensional place where stuff happens over time, or as a four-dimensional place where nothing happens [‘block universe’] — and if it really is the second picture, then change really is an illusion, because there's nothing that's changing; it's all just there — past, present, future.”

Remember what we said before — if a system is unchanging, it is timeless. So maybe the concept of time is made up, but even if time is an illusion, it is much more than a figment of our imagination. And that is where this whole discussion coincides.

Do you feel like you are understanding this now? What if I told you that superstring theory suggests that the universe actually exists in 10 dimensions at once?

The Universe is actually composed of 10 dimensions according to superstring theory. / Credit: National institute of Technology Tiruchirappalli

What Is Time Made Out Of?

Time is a dimension. Dimensions don’t have a composition. Dimensions are a way to measure and understand matter and energy. We live in a world defined by three spatial dimensions - X, Y, Z, and one dimension of time. On earth, this would translate to longitude, latitude, and altitude which represent the dimensions of length, width, and height. Once you include a timestamp on those, you are now representing space-time.

Time is composed of seconds, which can be broken down further as well. The modern international unit of time, the second, is defined by the electronic transition of the cesium 133 atom.

Who Founded Timekeeping?

Ancient Babylonian numerals. This was the sexagesimal system which has a basis of 60. / Credit: James Nickel

As humans, who are living in a civilized society, we need scheduling for our daily lives. Animals don’t consider time and rather rely on their circadian rhythms to function.

A fundamental part of being human, we evolved with the intense desire to measure anything we deal with, particularly when describing how events in our life would have or will occur. Since time is arguably the most important thing we have as humans, it has always been our natural inclination to measure it.

Humans, since the beginning of time, used to look up to the stars and use the sunrise and sunset to determine the time. But the system of timekeeping, as we know it, was first introduced by the Sumerians and also used by the Babylonians. The direct origins of this ancient system are still unknown, largely because it was developed in the period before the invention of writing. It is assumed that it could date back as far as 3,500 BCE. This ancient system that they developed is known as a sexagesimal system, which has a basis of 60. You can read about the history of timekeeping here.

Is Time Invented or Discovered?

Theorists propose a wide assortment of conclusions, such as: time is infinite, which means it had no beginning and will never end; time is cyclic, which also avoids the notion of a beginning and an ending; time is a concept we invented, which helps us get through life on a schedule; and time is an illusion, caused by our observation of events passing through space.

Here are some summarized thoughts on time from Stephen Hawking:

The universe is constantly expanding, and as you move backwards in time, then the universe contracts. If you go back far enough, about 13.8 billion years ago, the entire universe shrinks to the size of a single atom. This subatomic ball is known as the singularity and inside this massively dense speck of heat and energy, the laws of physics and time cease to function. So, time as we know it, as humans, ceased to exist before the universe started to expand. Before the big bang, time was bent, always reaching closer to nothing but not becoming nothing entirely. So, essentially, there was never a Big Bang that produced something from nothing. It just seemed that way from mankind’s point of view. Events before the Big Bang are simply not defined, because there’s no way one could measure what happened. Since events before the Big Bang have no observational consequences, one may as well cut them out of the theory and say that time began at the Big Bang.

And after writing this article – it is time for me to grab a beer.

By: Eric Mulder

Ancient Aztec Calendar Stone – the ancient Aztec, Maya, and Inca civilizations used complex timekeeping systems for the purpose of agriculture, worship, and political authority. / Credit: Dumbarton Oaks

Read more:

“Time.” Merriam Webster, https://www.merriam-webster.com/dictionary/time.
Helmenstein, Anne Marie. “What Is Time? A Simple Explanation.” ThoughtCo., November 26th, 2019, https://www.thoughtco.com/what-is-time-4156799#:~:text=Physicists%20define%20time%20as%20the,the%20present%20into%20the%20future.
Wolchover, Natalie. “Does Time Really Flow? New Clues Come From a Century-Old Approach to Math.” Quanta Magazine, April 7th, 2020, https://www.quantamagazine.org/does-time-really-flow-new-clues-come-from-a-century-old-approach-to-math-20200407/.
Martin, Sean. “Time is NOT real: Physicists show everything happens at the same time.” Express, July 4th, 2021, https://www.express.co.uk/news/science/738387/Time-NOT-real-EVERYTHING-happens-same-time-einstein.
Stok, Glenn. “Is Time an Illusion?” Owlcation, April 22nd, 2021, https://owlcation.com/stem/is-time-an-illusion.
Specktor, Brandon. “Stephen Hawking Says He Knows What Happened Before the Big Bang.” Live Science, March 2nd, 2018, https://www.livescience.com/61914-stephen-hawking-neil-degrasse-tyson-beginning-of-time.html.