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What is Time?

  1. Mar 16, 2009 #1
    What is time? What is the definition of time? What is this concept of time?
    Hey all, I asked my Physics teacher and many friends what time is, and non of them had a thought about it, Such a simple question yet difficult to answer. I would like to read your thoughts about time and your answers of the definition of time .

    Thanks for the time.
  2. jcsd
  3. Mar 16, 2009 #2


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    The best definition I've heard is :

    "time is that property of the Universe which prevents everything from happening all at once".

  4. Mar 16, 2009 #3
    try wikipedia

    basically says that time is a way of measuing a sequence of events...

    im sure there are people on here with a more profound answer than that though =]
  5. Mar 16, 2009 #4
    Lol, yes ive read some answers for different questions and thought that people hear would most likely as you have said have more profound answers.
    Its just a kool thing time, simple yet alot of people cannot answer it, if they do they ask themselves, how? why? can it be? and its funny and interesting to c the debates that occur. One physicist so far has this "My basic idea is that time as such does not exist. There is no invisible river of time. But there are things that you could call instants of time, or "Nows".
  6. Mar 16, 2009 #5
    The form of the question presupposes an answer of the form "Time is such and such a thing." What if the word 'time' does not refer to a thing and it is only the grammar of our language which misleads us to think that every noun is a person, place, or thing. If we examine ordinary language, we see that the meaning of the word 'time' is determined by its use, so perhaps a more neutral question would be "under what circumstances is it correct to use the word 'time' ?"
  7. Mar 16, 2009 #6
    My opinion is that to find out what is time, look at how time is measured.

    For example in a mechanical clock, time is measured by the hands pointing at a dot, then at the next instant at another dot. Maybe that is called a second. So a second is really just saying that "The hands of my clock has moved from a dot to the next dot."

    Hence when I want to measure velocity, I take the displacement of something per whatever unit of time I chosen. In other words, when I say that a particle moves 1 m/s, I am saying the particle moves 1m as the hands of my clock move the distance between one dot to another dot. In this way, it is clear that velocities are dimensionless.

    And because the hands of my clock move only in a direction, my time according to my clock is always in one direction.
    Last edited: Mar 16, 2009
  8. Mar 16, 2009 #7
    too put it simple the duration of between two points
  9. Mar 18, 2009 #8
    it feels like we use different concepts of "time"
    i think the classical time is the one we all know and love. its the same doesnt change. we all feel comfortable using time in that sense. i think gr, sr and all the recent break throughs in the in past 100 years have kind of screwed our meaning of time up. something that was once so set in stone that what we all knew was right was wrong?
    we always imagined time as an independant factor and i think its hard for us to visulise time being parrt of everything around us.
    so maybe there is not strict definition of time? and i agree with confinement in the sense that language is an issue with time. maybe foir the points iv said above..
  10. Mar 18, 2009 #9


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  11. Mar 18, 2009 #10


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    Its hard to say what time is, we all perceive time and its there. If you think of it in terms of the 4th dimension, the time taken for a resistor capacitor circuit to discharge is 0.69RC, which is a line through the 4th dimension. It’s also been said that if you were on a line representing time you would be walking along it (into the future) but looking backwards.
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