What Is Time? - Part 2

Written by:  • Edited by: RC Davison
Published Sep 30, 2009
• Related Guides: Big Bang

Continuing and diverging from what was mentioned in Part 1 into more of the specific uses and intricacies of time, we here survey notions such as biological time, quantum time, relativistic time, and provide some more information relating to the concept of time.

Introduction

Time can quickly regress to a very meaningless abstraction when you start thinking about it without staying within a context or schema...as can many things I suppose; time, however, seems to be by nature at once a very abstract concept, and a very nebulous, intuitive and fundamental part of existence. The irreversibility of our actions, accepted ideas of cause and effect, and activity in general seems to indicate some sort of "movement" of space; time itself does not necessarily "pass," or "move." Time can make explicit the symbolic nature of language, explicit because we see how crude the symbol is. Besides being part of the fabric of space-time, time can also be said to be a tool, which allows us to measure and locate; which, doesn't define the term as much as just replace it with another term. As to what exactly time is as part of space-time, that is ubiquitous to say the least.

Time can be said to encompass three different concepts: duration, simultaneity and succession.

Time: Circular vs. Linear

Time in general has been thought of generally as functioning along one of two paths: a linear one or a circular one. Although some postmodern thought has of course abolished the binary and integrated the two systems, and indeed in the industrialized societies time can be felt as both linear - a lifetime, and as circular - workweeks, months, years, which all construct a periodic and fluid forward motion, correlating to the linear birth, maturity and deterioration of our bodies. Even modern cosmology is torn on time being linear or circular, with many arguing that the big bang started time and that from there time continues ever forward as space expands, which some think may keep on expanding forever. Others argue that the big bang was an event in some larger cycle, a recycling or expanding and eventual collapsing of the universe in a "big crunch."

Biological Time

Biological time is generally thought to be some sort of internal awareness of time passing in plants and animals that is a type of innateness, or an unconscious awareness. It can be referred to as photoperiodism, a term which originated while studying plants, but has since grown to include animal behavior. Evidence cited for the existence of biological "clocks" would include the ability of some humans to wake up without alarm clocks at certain times each day, and that certain other types of animals appear through experiment to be able to measure time, such as in migration patterns of certain birds, or in certain behaviors of bees, such as the "dance" they perform upon returning to the hive after discovering the location of flowers. This "dance" involves movements that appear to indicate the amount of time needed to travel to the food, and the position of the food relative to the position of the Sun.

Biological time seems to be dependent upon observations from the natural world, and so be something that is learned. Time is kept by animals and/or plants observing changes in location of the Sun, the starry sky at night, the seasonal changes.

Relativistic Time

Relativistic time essentially describes time as part of the space-time fabric, something that is determined by the events of space-time, not visa versa, and requires time to be defined when put in relation to an observer or other event. Time in this model is a measurement of at least two simultaneous events. As Einstein put it, paraphrased: In relativistic time what we see is multiple events with different time epochs all occurring relative to the location and speed of some observer. So, in general: Time it is generally thought to be relative to place, speed, and curvature of space. One consequence is that time has been measured to function slower the closer to the light speed one is moving, relative to an observer moving much slower. Also a consequence, no material can travel faster than the velocity of light.

One apparent oddness that occurs due to time being relative, is the phenomenon, "time dilation." This can best be explained byThis image displays space-time with space the x and y axis, and time the y. It is important to keep in mind that another event or observer would have it's own time epoch, at a slightly different angle. The event O has occurred and the conical figure represents the extent of events that can be considered part of the history and future of O.  referring right to observed data: Mu-mesons, particles produced in cosmic ray showers, exist on average for 2 microseconds, relative to an observer traveling with them. These particles exist roughly 10 kilometers above the surface of the Earth, and so Mu-mesons that have been observed in experiment on the surface of the Earth must have travelled the 10 kilometers; however, they only exist for 2 microseconds and in that duration of time they could only travel less than a kilometer even at the speed of light, however, also a rule in relativity, all material particles travel at less than the speed of light; how could they travel the 10 kilometers? It turns out that with their increased speed their clocks have "slowed down," significantly, relative to us observers moving relatively astonishingly slowly. Thus no laws of relativity were broken.

An example of time dilation. An observer aboard an airplane measures the time it takes for a laser to be shot to a location on the airplane, and the same event is measured by an observer on the ground; because the observer on the ground is moving much slower than the observer in the plane, he will figure a different result. 

Relativistic time is contrasted against the Newtonian theory of an absolute time, a time that carries on at the same rate consistently everywhere in the universe regardless of any events that may be taking place or the speed of those events. Newtonian time is rigidly uniform and linear. Currently, however, most experiment has indicated that time is indeed relative to the simultaneous events that are measuring it.

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