C.T.Definitions

Time

TIME

The definition of time seems so easy and not worth a thought but we may want look at its concept first in order to settle this case. Time in general is not a constant and can only be measured among two objects in gravitational reference. The physically defined unit of time is the second, which is officially defined as "the duration of 9,192,631,770 periods of the radiation corresponding to the transition between the two hyperfine levels of the ground state of the cesium 133 atom."

Time on Earth

The earth day at this point is 23 hours 56 minutes and 4 seconds long. Expanding a minute within each 3.3 million years based on a constant slowing rotation of earth. Earth is traveling with various speeds pending on distance to the Sun around it making a full circle in 365.2422 days in reference to the eclipse varying only within the length of seasons within (precession). The all over extending distance between earth and Sun is at a rate of 15cm per year which extends the year mathematically speaking by 30 seconds within each 1 million years. So the time we live by is a simplified construct based on observation mainly focused on the day night pattern in order to allow a smooth connectivity within and among society.

Natural time patters are more various and show a high volume of differences matching among each other creating a complex system of interaction.

Relativistic Time

The idea of relativistic time is a direct result of Albert Einstein’s Theory of Relativity.

It was Einstein’s genius to realize that the speed of light is absolute, invariable and cannot be exceeded (and indeed that the speed of light is actually more fundamental than either time or space). In relativity, time is certainly an integral part of the very fabric of the universe and cannot exist apart from the universe, but, if the speed of light is invariable and absolute, Einstein realized, both space and time must be flexible and relative to accommodate this.

Although much of Einstein’s work is often considered “difficult” or “counter-intuitive”, his theories have proved (both in laboratory experiments and in astronomical observations) to be a remarkably accurate model of reality, indeed much more accurate than Newtonian physics, and applicable in a much wider range of circumstances and conditions.

Space-Time

One aspect of Einstein’s Special Theory of Relativity is that we now understand that space and time are merged inextricably into four-dimensional space-time, rather than the three dimensions of space and a totally separate time dimension envisaged by Descartes in the 17th Century and taken for granted by all classical physicists after him. With this insight, time effectively becomes just part of a coordinate specifying an object’s position in space-time.

Hermann Minkowski, Einstein’s one-time teacher introduced the relativity concept of proper time, the actual elapsed time between two events as measured by a clock that passes through both events. Proper time therefore depends not only on the events themselves but also on the motion of the clock between the events. By contrast, what Minkowski called coordinate time is the apparent time between two events as measured by a distant observer using that observer’s own method of assigning a time to an event.

An event is both a place and a time, and can be represented by a particular point in space-time, i.e. a point in space at a particular moment in time. Space-time as a whole can therefore be thought of as a collection of an infinite number of events. The complete history of a particular point in space is represented by a line in space-time and the past, present and future accessible to a particular object at a particular time can be represented by a three dimensional light cone which is defined by the limiting value of the speed of light, which intersects at the here-and-now, and through which the object’s world line runs its course.

Modern physicists therefore do not regard time as “passing” or “flowing” in the old-fashioned sense, nor is time just a sequence of events which happen: both the past and the future are simply “there”, laid out as part of four-dimensional space-time, some of which we have already visited and some not yet. So, just as we are accustomed to thinking of all parts of space as existing even if we are not there to experience them, all of time (past, present and future) are also constantly in existence even if we are not able to witness them. Time does not “flow”, then, it just “is”.

According to relativity, the perception of a “now”, and particularly of a “now” that moves along in time so that time appears to “flow”, therefore arises purely as a result of human consciousness and the way our brains are wired, perhaps as an evolutionary tool to help us deal with the world around us, even if it does not actually reflect the reality. As Einstein himself remarked, “People like us, who believe in physics, know that the distinction between past, present and future is only a stubbornly persistent illusion”.

Arrow of time

However, if time is a dimension, it does not appear to be the same kind of dimension as the three dimensions of space. For example, we can choose to move through space or not, but our movement through time is inevitable, and happens whether we like it or not. In fact, we do not really move though time at all, at least not in the same way as we move through space. Also, space does not have any fundamental directionality (i.e. there is no “arrow of space”, other than the downward pull of gravity, which is actually variable in absolute terms, depending on where on Earth we are located, or whether we are out in space with no gravitational effects at all), whereas time clearly does.

Time appears to have a direction, to be inherently directional: the past lies behind us and is fixed and immutable, and accessible by memory or written documentation; the future, on the other hand, lies ahead and is not necessarily fixed, and, although we can perhaps predict it to some extent, we have no firm evidence or proof of it. Most of the events we experience are irreversible: for example, it is easy for us to break an egg, and hard, if not impossible, to un-break an already broken egg. It appears inconceivable to us that that this progression could go in any other direction. This one-way direction or asymmetry of time is often referred to as the arrow of time, and it is what gives us an impression of time passing, of our progressing through different moments. The arrow of time, then, is the uniform and unique direction associated with the apparent inevitable “flow of time” into the future.