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Help me understand time.

  1. Feb 10, 2013 #1
    I'm not sure if this is the correct place to post. I'm not in the field and have no scientific education beyond basic Calculus and Physics in high school and early college courses. I do ,however, find physics fascinating and spend a lot of my free time reading articles and watching documentaries on the subject.

    One thing I've always struggled with is the concept of time. The way I view time and the way I've heard it described by many physicists do not line up. I hear it described as being "real". Somewhat of a fourth dimension and something that is definitely a tangible part of the universe.

    I have a hard time grasping that. To my logic, time is an invention of man. It only exists because we have memory of events that have happened and the intelligence to know that more will happen, but that it isn't "real". There is no past, no future. Just different states. What happened yesterday is gone and doesn't exist in any form anymore.

    Excuse my ignorance as I don't have the knowledge nor the vocabulary to properly describe it, but I think I described enough to get my question across.

    Is there an analogy or a way someone could describe time to me in the way it is looked at in the physics field?

    I apologize if this isn't the place for these questions.

    Thank you.
  2. jcsd
  3. Feb 10, 2013 #2


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    hi there
    welcome to the forums :)

    there's an old saying that goes ... "Time is natures way of stopping everything happening at once"

    Think about that comment of your's for a moment in the context of the saying I quoted...
    then you will realise time isnt something invented by man.
    everything in the universe is stille going to progress in "time" regardless of if you or I are around to witness it or not.

    Radioactive decay of a particular element is still going to occurr at a fixed rate of particles / unit time etc etc

  4. Feb 10, 2013 #3
    But what about when talking about (theorhetically) time travel, or the fact that time slows down near black holes. Is it really an actual phenomena being warped, or is it just our perception that changes? The person approaching the black hole will experience things normally, but those viewing it from a distance will see the person slow down.

    I guess I view time as more of an idea or a way for humans to measure existence rather than an actual reality or dimension. Maybe I'm not far off from the way the scientific community views it, but when listening to lectures and reading papers they always seem to talk about it so definitely and that it's as real and basic as light or the three dimensions.

    Maybe what I'm arguing is mere semantics or philosophy. I'm not sure if I'm thinking laterally of everyone else or if I'm just too dense to grasp the concept in the way they do.

    It honestly gives me a headache even trying to find the words to describe my view. I think I was hoping for a fairly simple explanation or analogy that would give me that "Oh okay" moment.
  5. Feb 10, 2013 #4


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    Time travel isnt in the realm of established physics yet so we wont go into that area

    blackholes .... thats only our perception looking from the distance
    for some one travelling in to a black hole they dont see anything different concerning the passage of time

    which is something we dont do here. we oly discuss known physics.
    we dont delve into fantacy and personal opinions specially if they well deviate from established and proven physics concepts

    well the comments in my first post are about as simple as there could be
    there would be many people on here that could give you all the formulae you could ever want to explain it all ;)

  6. Feb 10, 2013 #5


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    Sabiancym, Welcome to Physics Forums!

    “How can the past and future be, when the past no longer is, and the future is not yet? As for the present, if it were always present and never moved on to become the past, it would not be time, but eternity.”
    ― Augustine of Hippo, Confessions

    “Time is what prevents everything from happening at once.” ~John Archibald Wheeler

    "The only reason for time is so that everything doesn't happen at once." - Albert Einstein

    "People like us, who believe in physics, know that the distinction between past, present, and future is only a stubbornly persistent illusion." - Albert Einstein

    "When forced to summarize the general theory of relativity in one sentence: Time and space and gravitation have no separate existence from matter." - Albert Einstein

    Here’s an excellent essay, “The Nature of Time” by Barbour:

    superb description: http://www.integralscience.org/abouttime.html

    For even more, use Google search terms: “the nature of time”

  7. Feb 11, 2013 #6


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    Let's talk about real. I assert that the universe is real and exists outside your mind and independently of your sensations. If you close your eyes, the beings in front of you continue to exist even if you cannot see them anymore. Even if you die, the universe will still be there.

    Just because you cannot currently see what happened yesterday doesn't mean that yesterday isn't real, just as closing your eyes doesn't mean that today isn't real. Actually, everything we see has occurred in the past, because light takes some time to get to our eyes.

    Whether the future is real is up to some debate, but there are good reasons to believe that it is real, because of the time symmetry of our physical laws and because of relativity of simultaneity.
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