A MULTI-DIMENSIONAL WORLD VIEW

 
 

5. WHY DOES TIME GO FORWARD?

Time is not something that you can see or touch. It has no volume nor mass or energy. You will not be able to see it under a microscope. You can't find it in the dimensions of space or mass-energy. Yet it is absolutely essential for anything to exist. We are conscious of it because we can measure it by the days that pass and the steady progress of our wristwatches. Everything takes time. Time is a dimension of reality that we are very used to. But it brings some puzzles. One of these is 'why does time only go forward?'

Crown Range
Some years ago on a holiday in the South Island we travelled in our car over the Crown Range, on a road between Wanaka and Arrowtown. At the top we stopped to have a look at the stunning view that was before us. On the horison werre snow capped mountains. In the near distance below us we could see another road between Arrowtown and Cromwell, and also the tiny cars travelling on it. Some cars were just starting their journey to the right side of the scene, and others were many miles away nearly going out of our sight on the same road to our left.

The cars at the beginning of the journey seemed to be travelling so slowly, it would take them perhaps 15 minutes to get to the other side of our scene. As far as they were concerned it was a journey they would complete in the future. While we could track their journey as they travelled, we could also see both the beginning and the end of the journey at the same time.

               View from the Crown Range, NZ

The drivers of the cars below were experiencing time in one dimension. But I could imagine that I was in another dimension of time looking down on their time.

As I stood there looking I remember thinking that was how an eternal God sees us in time. I even felt a bit like God looking down on those cars. As far as we are concerned we are travelling through time, only able to see the present around us. We remember the past of course, but we cannot see the future. That is because we are in one dimensional time. God's view though is from more than one dimension of time, and he can see us throughout our journey, both when we begin our journey and the end of it, at the same time.

This illustration helps us to understand the dimension of time as we can imagine what it would be like to stand outside of one dimension of time. This is surely a necessary and useful technique in understanding the nature of any dimension.

What Makes Time A Dimension
Time is generally accepted as a dimension. Both Newton and Einstein accepted it as a dimension. Yet there have always been those who doubt it is a full dimension because it doesn't allow full freedom of movement in time. In terms of my definition of dimensions I beleive it passes with flying colours. It is helpful to look at the reasons for this as a test case for when we consider other dimensions.

Is it a unique property Logically we can see that the size of any object does not affect the passage of time. There is no overlap between the definitions of space and time. There is no time property in space, and no space property in time.

A good way to illustrate the uniqueness of length and time is to draw a 2D graph with the x axis representing length and the y axis representing time.

Fig 4. The axes of the dimensions of time and length can be extended by any amount without influencing the values on the other axis if they are at 90^o to each other.

In such a graph we could draw the growth of an object such as a tree and see how a tree grows taller over time. But every tree will have a different pattern of growth, so that the time and length values can be quite independent of each other.

Is Time Codependent? Both length and time are equally necessary for existence. Without one the other would not exist. Growth for example requires both length adn time equally.

Does Time Allow Movement? Different objects can be placed at different points on the time axis without limit. An object or event is limited in time in being able to be only in one place at one time. But time itself is not limited and can have various values placed along it as in the time-line shown.

Fig 5: A timeline showing how time has unlimited values

Even if you feel that only the 'now' time is real, because the past is gone and no longer exists, and the future doesn't exist because it hasn't arrived yet, you still have to have some duration of time for there to be any 'now' We are really forced to accept that all of time is therefore real, and that history is real.

The idea that time is only part of a dimension is a rather strange one, because if there is only a part of time existing that that part is the full dimension of time that we have.

We can see from the three tests we have applied that time has to be accepted as a full dimension, despite the limitation which we experience of time going only one way.

Time goes one way for us
Spilled milk doesn't unspill, you can't go back to see Great-Grandma, events begin and end, everything has a cause and an effect in time, we can remember the past but we don't remember the future.

We look forward in time, and we normally progress at the same rate as everyone else. Actually that depends on how fast we are moving, because if we travel at extremely fast speeds near the speed of light, we can slow our time travel down, which shows that time is actually linked to other dimensions and is not totally independent in its operation.

The interesting thing however is that no known laws of physics show that time should move just forward.  All equations of time show that it should move backwards as easily as forward. Just as we can run a video backwards, so time should be able to run backwards also. So why does time go only one way?

Brian Greene, considered one of the world's leading physicists believes the answer lies in entropy, "The future is indeed the direction of increasing entropy." [TFOTC pg 175]*  Entropy is the process of disorder or decay in the universe, where everything loses order and energy as time progresses. Another way of putting this is that the forward motion of time is actually the increasing disorder of the universe. Time can't go backwards because matter and energy can't become more ordered.

Actually the argument that entropy causes time to move forward is rather circular, and we are left wondering if the chicken comes before the egg or the egg before the chicken. Because entropy also goes in only one direction which is to increase with time. Because time goes forward it allows decay and disorder which would not be able to otherwise occur. How can we work out if it is forward time that produces entropy, or entropy produces the forward time? Blaming entropy for time's problems is passing the buck!  Entropy could just as easily blame time for its problem.

Entropy is a property of matter and energy. Our experience of time going forward seems to have nothing to do with matter or ernergy. Time intervals have their own clock in our minds that recognises time intervals, that provides a logical before and after for events, and is confirmed as we see the regular motion of a watch or the movement of the sun. Time is not tied to matter and energy. The answer has to be in the nature of time itself. What Brian Greene does show us however is that modern physics does not yet have an adequate answer about the nature of time.

A Simple Explanation
The simple explanation for time's arrow may be that time is one dimensional, in contrast to space which is 3D. Three-dimensional space allows us freedom of movement in all directions. We can stop, go forwards and backwards or up and down. Its great. But in one dimension of space there is not the same freedom.

A length of string which represents one dimension may seem to indicate that we could go either forward or backward along it. But possibly because we are already moving forward and facing in one direction, in practice we could only keep on going forward because there would not be enough space in sideways terms for us to turn around to go back. The same could happen with one-dimensional time. Once time's rate was set at the beinning of the universe perhaps its one dimension doesn't allow us to slow down or stop in order to turn around and go back in time. The one direction of time not only doesn't go backwards, it keeps going at the same rate.

Saying the same thing in another way, in one dimension of time we have no choice as to the time-line we are on. All possible time-lines are on top of each other because there is only one dimension to fit them in. So what we experience of time is all that there is in our dimension. The time-line that we are on has just one rate and one direction because it is only one line and has to have a rate and direction to be a time-line at all.

Two Dimensions of Time
What would two dimensions of time look like? Anyone can draw two dimensions of space, height and width, onto a flat surface, so allow me to draw below two dimensions of time onto your flat screen.

Fig 6. Two dimensions of time. 'T' are three parts of a one dimensional time line going at normal earth speed. A and 'B' and 'C' are any other directions of time that can be drawn on a flat surface. From T's perspective A's time will seem to have shrunk, and therefore A will be slightly slower that T (A's 1 hour may look like only about 55 minutes to T. B's time will have shrunk further, and therefore will be much slower than T or A. Although to themselves exactly the same time has elapsed for both A and B, indicated by the same length of their time lines. C shows how time may be able to reverse, but in practice this may not be possible even in two dimensions.

We are not used to thinking of time in two dimensions. So don't be surprised if you can't easily imagine what that would be like. What it means in practice is that objects in a second dimension of time will be able to have their own independent time clocks with their own time scale.

When we think about it, we do actually have some flexibility with time when we remember Einstein's Theory of Relativity, where it has been shown that at near the speed of light, time can slow down from the point of view of a stationary observer. Does this show a second dimension of time coming into play? Certainly it shows how the one time dimension we have is not a closed dimension.

Three Dimensions of Time
If we extend this idea to three dimensions of time, we can show this by drawing on the surface of a balloon. If we draw a straight time line on the balloon we can see how such a time line can go right around the balloon joining up with itself again, indicating that in three dimensions time has no beginning or ending.

The mathematics of time can be worked out more thoroughly that what I am indicating here, but I am trying to keep this as short and simple as possible.

Fig 7. Three Time Dimensions. A 3D time-line (E) shown in 2D on the surface of a sphere. It is able to continue around the full sphere, so shows that 3D time can have no beginning or ending. Time-lines A, B & C show how lines starting from one point in time can end up at a different points on timeline E, therefore demonstrating time travel, or a cause utside of our 1D time being able to have a common effect at different times on timeline E. [See also BTC pg 69]

Three dimensions of time show how it is possible for there to be a cause outside of 1D time that can have an effect on the time-line E of earth (for this example E would not be a full circle because the earth time-line is 1D). We can also see how thta cause does not have to have a beginning. Any 1D or 2D time-line has to have a beginning, but a 3D time-line can have no beginning or ending.

Three dimensions in time would give anything full freedom of movement in time. Is this what the Bible means when it talks of eternal life? "Whoever believes in the Son has eternal life." [John 3:36] Eternal means 'all time'.

This is not the picture that some may have of heaven being a place of timelessness (whatever that means), or of everlasting time that is endless one-dimensional time. How boring that would be! But eternity with God will be exciting because there will be so much more to do with all the freedom of time available to us.

Life in eternity with God will be exciting because there will be so much more to do with all the freedom of time movement available to us.

BTC. 'Beyond the Cosmos', Hugh Ross, Navpress, 1999
TFOTC. 'The Fabric of the Cosmos', Brian Greene, Knopf, 2004

Rev Brian Brandon, May 2004

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