Most people are aware that we live in a four-dimensional Universe.  The three dimensions of space allow us to see three-dimensional shapes, like cubes and spheres.  If we lived in a world of two-dimensional space, we would instead see squares and circles with zero thickness.  Stephen Hawking has said that such a two-dimensional space could not support life, as a 2D being could not both eat and defecate?  A shape with two openings could not hold itself together, and would fall apart or bleed to death (try to draw it and you’ll get the point).

Of course, the fourth dimension of our Universe is time.  Time is an essential ingredient in the space-time continuum.  Without the dimension of time, the 3D shapes we see would not change.  Everything would be steady state, and there would be no need for the word transient.  Put simply, what is time, but the entity preventing everything from occurring at once? 

I cannot imagine a universe without the dimension of time, as it would negate one of man’s most wonderful tools: memory.  No information would need to be retained, because life would be reduced to a single instant.  On the bright side, you would have a good excuse for forgetting your anniversary.

When discussing dimensions in a scientific scope, it should be mentioned that most physicists today believe that there must be more than three dimensions of space out there, as string theory does not seem to work with so few of them.  Some physicists believe that there must be at least six additional dimensions of space, yielding a 10D world, while others argue that there must be more.  We can then think of the world we observe as a subset, or cross-section of a much bigger picture.

Leaving the actual number of spatial dimensions as an open question, let us focus on the remaining dimension of time.  The concept of time is so fundamental for all of us in terms of how we live our lives.  It is sometimes hard to conceive that it was man that invented the second, the minute, the hour.  You and I use these timeline yardsticks on a regular basis to measure the passage of time.  It is easy to approximate all three quantities without the use of a watch.  Your pulse is likely to beat once every second.  One minute is the time it takes to tie your shoes.  An hour is the longest consecutive period of time I can shop at Wal-Mart before losing my mind. 

Our biological clock is much in tune with the length of time we get when we string twenty-four hours together.  Man coined the term ‘day’, but it is of course based on the approximate length of time it takes for the Earth to make one full revolution.  The Sun’s rise and set is governed by this period of time, and life on Earth is dictated by the Sun, as it provides all of its energy.  The week and month are useful collections of days, and must be carefully considered when planning ‘sick days’.

That other all-so-important unit of time, the year, is governed by two things: the mass of the Sun and the distance from the center of the Sun to the center of the Earth when they are furthest apart (also known as the semi-major axis).  A year is a useful measure of time, as the seasonal cycle repeats with the passage of each one.  It is therefore a great span of time to repeatedly recognize and celebrate the aging of a person, i.e. a Birthday.  I am not sure where the cake tradition comes from, but I am thankful for it.

Things get a bit hazy after the ‘year’.  We can string ten of them together and call it a decade.  This amount of time usually represents a stage of life as follows...

Decade 1: Grow big and strong
Decade 2: Go to school
Decade 3: More school and then work
Decade 4: Make babies and watch them grow
Decade 5: Work a lot so that you do not need to work forever
Decade 6: Empty the nest and maybe retire
Decades 7 and beyond: the rest

The decade is also of cultural significance for many of us, often described by the popular music of the time, by political movements, and far too often, by wars.  Ten decades make a century, and this amount of time is often internalized as well; we see it as our maximum life span, although some push the envelope, living on “borrowed time”.  Like decades, centuries are often described by the events that they contained, although they are maybe best described by the technological advances that occurred within them.

The nineteenth century gave rise to the industrial revolution due to the advent of the steam engine.  The twentieth is the century of travel thanks to the automobile and airplane.  I expect that the twenty-first will be one day looked back upon as a quantum shift – a century where everything became automatic and instantaneous, and when the keys to energy and DNA manipulation were unlocked.  That sounds like a lot, but one hundred years is a long time when a species becomes as advanced as ours.

A millennium is almost beyond the comprehension of a human being.  A historian may try to conglomerate events and call it a millennium, but multiple lifetimes are nearly impossible for a human being to visualize.  Some religious leaders look back two millennia to the birth of Jesus, and others look back five millennia, to the grand creation.  I see a millennium as a hick-up as far as the universe is concerned.  We are now 13.7 billion years from the big bang.  If we call that span of time the age of our universe, then a millennium is to it what 3.8 seconds is to a one hundred-year-old man.

Evolution is a very slow process.  For life, millions of years represent a useful span of time, where noticeable changes may occur in a biological sense.  For the universe, evolution is a multi-billion year long process.  This is the massive amount of time it takes for galaxies and solar systems to form.  Time is a word we throw around, but it is a hard one to truly appreciate as it began to tick so long ago; we cannot imagine it.  If you spent your whole life watching a single rock, and documented its changes in a notepad, you would leave a blank page with your passing.

The scale of time is something we are familiar with.  Most of us are not at all familiar, however, with the true nature of time.  It is incorrect to think of time as a firm measuring stick.  Time is malleable, like a stick of gum.  The speed of light is constant in a vacuum; that is a law of physics.  To ensure that this law is maintained for all observers, time actually dilates accordingly, based on the speed of the observer (this is known as special relativity).  It is a very real challenge for physics students to conceive that clocks, be they mechanical or biological, tick slower for people who are moving near the speed of light.

 

Fortunately, it is not something most of us need concern ourselves with, as none of us ever travel anywhere near 300,000 km/s.  Still, the slight time dilation experienced by relatively fast-moving satellites require that the onboard clocks be adjusted to tick slightly slower, so they remain synchronized with those on Earth.  Without this adjustment, GPS technology would be utterly useless, and you would arrive at the wrong destination ... late.

Time is relative in other ways as well.  A hundredth of a second may feel like an unimportant unit of time, but try telling that to an Olympic sprinter for whom victory was separated by just that amount of time.  Microseconds represent a lifetime for certain particles, whereas they go by unnoticed by us: it is the time it takes the light of a lightning strike to travel across a field and into our eyes.

All of this may make us feel at a bit of a loss.  We cannot appreciate microseconds, nor can we conceive of actual long passages of time.  Worse still, time is not a concrete thing, so even the units of time that we can appreciate are different depending whose space ship you are travelling in.

Well, it could be a whole lot worse.  If you suffer from Alzheimer’s disease, you know all too well that time is of little use without memory.  Some philosophers argue that there is in fact no time without memory, just as a tree that falls in an empty forest does not produce any sound.   Without a conscious observer to record the passage of time, there is no time.

We tend to take the passage of time for granted, asking not what it is, but rather how we should spend it.  It is sometimes nice to take a step back and see time for what it is: a dimension without which life would simply be unimaginable.  Life is a collection of moments connected in series.  Time is the entity responsible for arranging these events in chronological order.       

On June 30, 1905, Albert Einstein proposed that the Universe worked much different than the way anyone alive had supposed it did.  In short, Einstein’s theory of special relativity claims that space and time are not absolute quantities, but are rather malleable, relative scales of measurement.  This astonishing statement, which has not been disproven in the 105 years that have passed since its inception, should boggle your mind unless you have been aware of it for some time.  As I tell my Modern Physics students, if special relativity does not disturb you to the core the first time you hear it, it is because you did not really hear it.  The theory, which has attained law status, goes against everything we observe in our day to day lives.  For this reason, special relativity, which shows that classical physics only applies perfectly to relatively stationary objects, went unnoticed for so long. 

It should be noted that Einstein did not notice that time dilates for two objects moving at relative speeds, he just had a strange intuition that light was special, and wished to understand it better.  His journey towards this understanding required a certain leap of faith.  When Einstein was on this historic path of discovery, he told his friends that he wanted to get inside the head of God, to which they replied, “Could you tell him to pick my 6/49 numbers?"

Special relativity is based on two claims, or postulates, which, at first, seem to be benign enough.  The first states that the laws of physics are the same for all inertial reference frames, and that no one frame is preferred over another.  An inertial reference frame is one that is either still or moves at a constant speed.  This postulate essentially says that the Universe operates the same for all individuals, even if they are moving with respect to one another.  Even though we may experience life in our own unique way, we are all governed by the same rules.  Moreover, everyone’s unique experience of life is equally valid; no point of view is preferred.  The Universe is equitable.

The second postulate is where the big leap of faith occurs.  Einstein made the assumption that the speed of light in a vacuum is the same when measured in any inertial reference frame.  This is a bold statement, which essentially claims that the constancy of the speed of light is a law of physics.  No matter what speed you are moving at, you measure that light whizzes by you at the same 300,000 km/s that it would if you were stationary.  It shows that Einstein loved light, and actually favoured it over space and time.  The compelling truth that emerges when we examine this postulate carefully is that time and space must adjust, or bend accordingly, to allow this apparent anomaly to take place.  His blind faith in the speed of light was surprisingly well-placed – that time and space adjust, or dilate, for objects moving at high speeds has been verified experimentally countless times, and never disproven.

As you warm up to this concept (if you had never heard it before, it will take some time to accept it), let us relate it to the very hot topic of religion (pun intended).  Special relativity has so many philosophical implications.  It states that we all view the world with the same lens, but make different conclusions on it because our reference frame is always unique.  Time and space bend to uniquely wrap around our perspective when we are moving at a specific speed.  Is our perception of time and space correct?  Is it wrong?  It is neither – our perception simply is our perception.  Everyone comes to a unique conclusion about life, since their reference frame is unique.  Our lives exist in the same Universe, and obey all the same rules, yet we observe life differently than the next person.  However, and this is key, no reference frame is preferred; all are equally correct.

The relativity of simultaneity is a direct consequence of special relativity.  It states that to one person that is still, two events can be seen as simultaneous, but to someone moving relative to you, those same two events are observed to have occurred at different times.  Can they both be right?  Yes.  Both viewpoints are correct.  To the stationary person, the events were simultaneous, and to the moving person, they were not.  There is no absolute here, and the same is true about religion.

No one religion is more correct than any other.  There, I said it.  Someone has to.  Person A says that their invisible creator is responsible for their life.  Person B says that the creator is actually some other entity.  Person C says that in fact persons A and B are both wrong, as there are several creators.  Person D says you are all wrong, as the Universe can exist without any creator.  Special relativity argues that all religious beliefs are equally valid.  We all lead a specific life, which leads us to relatively different observations and points of view.  If you accept special relativity, then you must also accept that there can be more than one correct answer or solution to the origins of the Universe. 

Introductory Mathematics leads us to believe that if solution 1 ≠ solution 2, then both cannot be correct.  Yet, the math of special relativity is elegant, and says the opposite is true.  Why?  It is because both solutions correspond to two unique questions.  Religious leaders wish to generalize their respective faiths, as though they should apply verbatim to all others.  What these leaders fail to recognize is that the question for all of their followers is actually unique.  Our personal viewpoint is relative, and thus, so too is the question, “What is life?”  Clearly, the answer should vary from person to person.  If time passes at the same rate for two people, then they are not moving with respect to one another.  In life, we are all set in relative motion with respect to our views on life.  As such, our viewpoints are equally correct, and most importantly, not necessarily transferrable.

In science, we must agree to disagree sometimes.  Two different observations of the same event can be different and also valid if they come from separate perspectives; in fact, they must be.  When Einstein declared that both time and space are relative, the scientific community took some time to accept this possibility.  They eventually came around, and today, use the theory to ensure successful operation of GPS technology among others.  Indeed, the clocks onboard satellites, which move fast compared to the surface of the Earth, are adjusted to tick slightly faster.  It is the only way they can remain synchronised to our clocks on Earth.

The religious community is historically slower to adapt than the scientific community is.  It is not my intention to impact anyone’s religious views.  My hope is that there will come a time when no one tries to impose their religion onto someone else.  Special relativity proves that such efforts are fundamentally flawed.  Religious views should be based on observation and reason, not authority.  Somehow, religious leaders got this one ass backwards. 

You know how some people take offense when their religion is questioned or challenged?  That is how I feel when proven science is ignored.  Special relativity is a case where science encourages open-mindedness for all perspectives.  It offers validity to everyone’s impression.  The most progressive of religions ought to consider implementing George Carlin’s unwritten commandment into their list of life values: “Keep thy religion to thyself.”  I don’t mean that you shouldn’t share your views; I just mean that you must never enforce them.  The distinction between the two is responsible for the vast majority of the ugliness in the world.  I beg of you, that when you make a leap of faith, make one akin to Einstein’s.  Leap from a place of inquisitiveness, not authority.