Time out of Mind

Time is a familiar but mysterious concept. We think about and use it every day, yet it is difficult to describe what it actually is. Saint Augustine puzzled about time when he wrote, “What is time? If no one asks me, I know. But if I wish to explain it to someone who asks, I know not.”

Poets and philosophers throughout the ages have eloquently tried to capture how their senses perceive Time by using phrases such as; “Time is fleeting“, “Time waits for no man“, “Time heals all wounds” and “Time stands still“. None of these phrases, however, succeed in advancing a deeper understanding of the mystery that is Time.

My background in engineering led me to wonder about the concept of Time beyond the typical artistic and philosophical musings – to explore what science actually had to say about the mysterious subject. So, with curiosity and time on my hands, my search led me to an online course called the Physics of Time. In this month’s blog I will share some of the interesting insights I learned about Time from that course.

Time can be examined from two separate scientific perspectives. The first is a biological perspective which deals with internal human body clocks and how the brain processes and perceives time. The second is an external cosmological perspective which has to do with the origin and evolution of time in the known universe.

Human bodies and brains have a natural way to recognize the passing of time because we have predictable biological clocks – like breathing and the beating of our hearts – that exist within each of us .

With a heart rate of about 60 beats per minute and a lifespan of roughly 70 years, the human heart will beat approximately 2 billion times. Chickens have a much faster heart rate of about 275 beats per minute, and live only 15 years – but their hearts, in the end, will also have 2 billion lifetime heartbeats.

Science has observed that the hearts of most animals will beat somewhere between 1-2 billion times but there is an inverse relationship between heart rate and lifespan. In general, the faster the heart rate, the shorter the life span. I wonder if those animals who live fast and die young perceive time any differently than us longer life-span creatures.

Besides the heart and the breath, Neuroscientists have identified three kinds of timekeeping devices inside our brains. One part of the brain keeps track of what time of day it is, another part keeps track of how much time has passed while doing certain tasks and still other parts of the brain serve as alarm clocks for events set to happen in the future.

Different neuron pulses working together in the brain help us to perceive the passage of time. These pulses can be affected by stimulants, such as caffeine, and depressants, such as alcohol which interfere with neurotransmitters in ways that make our internal clocks speed up or slow down.

We experience other biological processes that don’t repeat themselves but still contribute to our awareness of time passing: We age; we think; we make choices; we plan for the future; we remember the past. All these different aspects of time are crucial to what it means to live our lives and be human beings. Perhaps the most important aspect of our awareness of the passage of time is the accumulation of experiences.

People have observed that when they are focused on a task, they don’t pay as much attention to the outside world or to their internal clock. This causes their internal timekeeping devices to slow down while the outside world speeds up. For example, I am surprised how quickly the hours elapse while I am engrossed watching my favorite sports teams compete in a big game.

In contrast, when we are bored and not focused on any one task, the opposite effect happens. Our internal clock seems to go faster while the outside world seems to slow down. For example, when I am stuck on an airplane with nothing to do, the plane trip seems to last forever.

Scientist have reported that subjects in high-stress experiments recollect that time slowed down for them during stressful events. One theory behind this phenomenon is that the more memories we accumulate, the more time we think has passed. Our brains, when we are in a high-stress situation, does its best to record absolutely everything. It accumulates a huge amount of data, so when you think about the situation afterward, you have more memories to leaf through—and, therefore, it seems as if more time has passed.

This theory gets support from the fact that time seems to pass more quickly as we age. Summer seemed to last forever when we were children, but it seems to rush by as we get older. It may be that when we were young in the summertime, such activities as going to the beach were new to us, but as we get older we experience fewer interesting new things. Our brains don’t take in as much new information and we create fewer memories than a child would; thus, time seems to pass more quickly for us compared to when we were a child.

To understand Time from a cosmological perspective is difficult because it requires the human mind to reckon with complex physical laws of the universe that were set in place at the beginning of the universe – and to consider hard to grasp time spans that are billions of years in length.

Most physicists believe Time began approximately 13.8 billion years ago with a singular event known as the Big Bang – the so called “birth” of the universe – a point where space underwent rapid expansion and the laws of physics as we understand them came into being. The Earth is about 4.5 billion years old, so it is a substantial fraction of the age of the universe.

At the beginning, all matter in the universe was densely packed and its temperature was extremely high. About 380,000 years after the Big Bang, the universe cooled sufficiently to allow the formation of subatomic particles and simple atoms. Giant clouds of these primordial elements later coalesced through gravity into matter, eventually forming early stars, galaxies and the other astronomical structures that are observable today.

The feature of matter that is inextricably linked with time is called entropy. Entropy is a way of talking about the disorderliness of “stuff” in the universe. It is the natural tendency of things to lose order over time. For example, a whole egg is very orderly, but if we break the egg, it becomes disorderly; if we scramble the egg, it becomes even more disorderly. A scientist would say that the egg moves from a low entropy state to a high entropy state.

In the long run, nothing escapes the Second Law of Thermodynamics

Entropy is the only quantity in the physical sciences that seems to imply a particular direction of progress, sometimes called an arrow of time. As time progresses, the second law of thermodynamics states that the entropy of an isolated system never decreases over significant periods of time. Entropy measurement can be thought of as a clock and things only happen in one direction of time – not the other. The past is always defined to be the direction in which entropy was lower.

The pull of entropy on matter is relentless. Everything decays. Disorder always increases. The increasing entropy of our universe over time underlies all the ways in which the past is different from the future.

It is the reason why you can disperse the scent of perfume from a bottle into a room, but cannot put the scent back into the bottle; the reason why you can mix cream into your coffee, but cannot un-mix it; the reason why cars eventually break down; the reason you remember the past and not the future; the reason you are born young and grow older; the reason you can make a choice about what to have for dinner tomorrow, but not about what to have for dinner yesterday.

When energy is in a low-entropy form, it can do useful work. When energy is converted into a high-entropy form, it becomes useless. We have fossil fuels sitting in the ground with energy in them in a concentrated form. We can extract the energy to do useful work because the entropy of the fuel is low. Once the fuel is burned it is converted to its high entropy form and it can no longer perform useful work. You can heat a room in your house by burning coal, but you cannot cool off a room in your house by unburning fuel and turning it into coal.

The common thread in these examples is irreversibility: Something happens in one direction, and it is easy to make it happen, but it does not happen in the other direction, or if it does, it is because we put effort into it. It does not spontaneously happen. Things go in one direction of time. They do not go back all by themselves.

It’s not time itself that treats the past, present, and future differently; it’s the arrow of time, which is ultimately dependent on all the “stuff” we have in the universe. It is the arrow of time that gives us the impression that time passes, that we progress through different moments. It’s not that the past is more real than the future; it’s that we know more about the past. We have different access to it than we have to the future.

Stephen Hawking combined the biological and cosmological elements of time into three distinct “arrow of time” components. First, there is the thermodynamic arrow of time—the direction of time in which disorder or entropy increases. Second, there is the psychological arrow of time. This is the direction in which we feel time passes—the direction of time in which we remember the past, but not the future. Third, there is the cosmological arrow of time. This is the direction of time in which the universe is expanding rather than contracting.

At the moment of the Big Bang our universe was in a condition of very
low entropy and very high organization. That’s what got time started in the way we experience it in our everyday lives. Ever since the Big Bang, we’ve been living out the process by which the universe increases in entropy. That’s the influential event in the aftermath of which all humans live.

At this point in time the universe is in a condition of medium entropy. It is today that we have galaxies and stars and planets and life on those planets. Complexity depends on entropy; it relies on the fact that entropy is increasing. We don’t have to worry about how complexity can arise in a universe that is evolving. The simple fact that entropy is increasing is what makes life possible.

Scientists have confirmed that the universe continues to expand. Distant galaxies are moving away from us, and the farther away they are, the faster they are receding. The amount of space between us and the other galaxies is increasing.

The second law of thermodynamics predicts that the total entropy of the universe will continue to increase until it reaches equilibrium. The universe will calm down and become colder and colder. Everything will scatter to the winds, evolution will stop and we will have empty space once again. It is speculated by some that after a googol (1 x 10 to the 100th power) years from now, our universe will be empty space and that empty space will last forever.

There are some however who believe instead that multiple universes exist. According to this idea, the Big Bang was an event that is quite small in the history of a much larger multiverse. We see only a finite bit of the universe;
perhaps farther away than what we can see, the universe looks very
different. The fact that our own universe is inflating gives some credibility to this idea.

Those who talk about the possibility of a multiverse are simply observing that there is a barrier in our universe’s past beyond which we cannot see.
Is there a finite amount of stuff out there? Is there an infinite amount of stuff that works exactly like the stuff we can see? Or is there an infinite amount of stuff and conditions that are very different from place to place? Until scientists can answer these questions, they can only speculate.

Regardless of which theory you believe about how the universe will ultimately evolve, we can say that all scientists agree that the universe is a complicated system, embedded in an environment that is far from equilibrium and that there is something called entropy that characterizes the organization or disorganization of us and our environment and results in the evolution of matter.

No discussion of Time would be complete without mentioning
one of the most important contributions ever made to science – Albert Einstein’s 1905 publishing of the Theory of Special Relativity. Before Einstein, physicists thought of time as simple and absolute, a steady linear flow separate from the three dimensions of space.

Einstein showed that time is not simple and absolute but is actually influenced by speed and gravity. He stated that there is a link between motion in space and the passage of time. Space and time are fused together in what Einstein called 4 dimensional space-time.

Einstein theorized that Time runs more slowly for an object if it is in motion. Scientists proved this by synchronizing two atomic clocks and placing one clock in a stationary location and the other clock on a plane that was flown around the world. Upon landing, the clocks were no longer synchronized, the one that had been on the plane was milliseconds behind the one that was stationary – indicating less time had elapsed for the moving clock.

With Einstein’s relativity discovery, there is no such thing as one moment of time throughout the universe that everyone agrees on. Space and time are not absolute; they are relative – which means what we call time can be different for different observers.

How much time passes for an object depends on how you move through the universe. The network of satellites in space that carry precision atomic clocks for the global positioning system must be constantly compensated because they “lose” seven microseconds per day compared to ground clocks that are operating in a “slower time stream”.

The faster something moves, the “slower” it ages. Physicists call this effect time dilation. Theoretically, under its influence, a space voyager could return to Earth after a 20-year voyage to find himself hundreds of years in the future. To carry time dilation to its absolute extreme—as we approach travel at the speed of light, it is possible that time stops and immortality begins.

Space-time, Einstein’s four-dimensional reality of our universe, is a collection of an infinite number of events, just as space is a collection of an infinite number of points indexed by the three dimensions of space. Just as we think of all space as being “out there”, Einstein said we should think of all time as also being out there: “The difference between Past, Present, and Future is only an illusion, however persistent“.

I must admit that my deep dive into the science of time raised as many questions as it answered – but that doesn’t mean my study was a waste of my time. On the contrary, I gained some wisdom about life and walk away with a list of important things to remember that will help me make the most of whatever time I have left.

• Remember that we are very, very small – Mankind is like a grain of sand in the vast Sahara Desert, occupying an infinitesimally small place in the universe. The astronomer Carl Sagan said that earth is nothing more than “a mote of dust suspended in a sunbeam and our time amounts to nothing more than a blip“. Compared to the enormity of the cosmos and the eternity of time, it is wise for us to keep an attitude of humility, remembering the short duration of our life and the insignificance of our daily struggles.
• Be grateful we are alive – In a world full of matter, humans have been fortunate to form over time into a remarkable collection of atoms that are alive, conscious and capable of love and memory. As far as we know, we are the most advanced form of life in the wide universe. In his book Cat’s Cradle, Kurt Vonnegut expresses wonder and gratitude for the gift it was to have become what he called some of the “sitting up” kind of mud in the universe.

“God made mud.
God got lonesome.
So God said to some of the mud, “Sit up!”
“See all I’ve made,” said God, “the hills, the sea, the
sky, the stars.”
And I was some of the mud that got to sit up and look
around.
Lucky me, lucky mud.
I, mud, sat up and saw what a nice job God had done.
Nice going, God.
Nobody but you could have done it, God! I certainly
couldn’t have.
I feel very unimportant compared to You.
The only way I can feel the least bit important is to
think of all the mud that didn’t even get to sit up and
look around.
I got so much, and most mud got so little.
Thank you for the honor!
Now mud lies down again and goes to sleep.
What memories for mud to have!
What interesting other kinds of sitting-up mud I met!
I loved everything I saw!
Good night.
I will go to heaven now.
I can hardly wait… Amen

Kurt Vonnegut “Cat’s Cradle”

• Embrace change – Entropy is a natural law, we can’t repeal it or wish it away. Entropy is what helps us to evolve and it is what makes life complex and interesting. So, rather than fight change – which is inevitable – it is healthier for us to embrace the change in our life and determine how we can best use it to evolve in ways that make us better.
• Be Mindful of the Present – Sometimes it can be impossible to focus entirely on the present because it comes with an echo of the past and a foretaste of the future. Our minds typically refuse to stay in the present, constantly regretting a past that can never be undone or anxiously awaiting a future that may never arrive. The mind can be trained with Mindful Meditation techniques that teach us how to live “outside of time”, focusing our attention on each passing moment, slowing our perception of time and relieving us of our anxiety over past and future events.
• Get busy and try something new – Time moves more slowly for a body in motion and we perceive the passage of time as moving slower during those moments when we are creating new memories. That tells me if I want to make the most out of time I should be pursuing activities that keep me moving and learning new things.
• Don’t rule out the Divine – There is agreement among scientists that the universe started in a dense state of very low entropy and that it is expanding over time towards higher entropy. The questions that still puzzle scientists however is what triggered the Big Bang event and why did the universe start in such an unlikely state of low entropy? As a man of science and a man of God, I am somehow comforted when all questions cannot be answered and there is room in the discussions for us to ponder the possibility of a divine hand in the origin of the universe.

May you enjoy your own personal time travel trip – here’s hoping that you live every moment and love every day before your precious time slips away.