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How we measure time

  1. Oct 7, 2015 #1
    Just as a fore-note, I understand this question may be hard to answer, and I'm sorry if I slip into philosophy.
    We humans can understand time on our scale, but we cannot necessarily comprehend events that occur say on a quantum level, they seem to go to fast. Now my question that arises is that how fast time passes objectively, or is how fast time appears to pass relative to how many points the clock you are using records? I was thinking that the second interpretation seemed more correct, because why should the universe operate just fast enough, objectively, so that we humans can comprehend events that occur? Now if this is the case, than what does that mean for the conclusion of general relativity that time slows down or speeds up based on how curved space-time is?
    Thanks in advance, and I understand this question might have no scientific interpretation but I'm really curious.
  2. jcsd
  3. Oct 7, 2015 #2
    We measure time in seconds (or other units) because that's what we as humans are comfortable with measuring time as. Relativity works the same either way.
  4. Oct 7, 2015 #3
    The most important thing to remember is that time is relative for other observers, from the first person view time passes normally... a second always seems like a second, and physics remains consistent.
  5. Oct 7, 2015 #4


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    Time passes at a rate of one second per second, always. If you have a clock with a granularity of one microsecond, this means that there are one million ticks in a second. If the clock has a granularity of one picosecond, this means that there are one billion ticks in a second. There is no deep philosophical meaning there.

    We comprehend the things that occur at rates that match what we can usefully perceive. There are events that occur faster than that. There are events that occur more slowly than that. It turns out that our ability to comprehend events that occur on a time span of seconds is useful to our survival in an evolutionary sense. We use labels for time that match our ability to usefully perceive. No deep philosophical meaning there.

    General relativity does not say that time speeds up or slows down. It still proceeds at a rate of one second per second locally. What general relativity says is that using a clock over here to measure an elapsed second over there has complexities relating to the curvature of space-time.
  6. Oct 7, 2015 #5


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    Staff: Mentor

    There is no philosophical issue here: we pick units that are useful to us. That's what we always do. It doesn't tell us anything philosophical about scales any more than the difference between meters and nano-meters does.
  7. Oct 7, 2015 #6
    First you should know that there are two interpretation or arrows of time:-
    The thermodynamic arrow. And
    The psychological arrow.

    The thermodynamic arrow of time is based on the second law of thermodynamics.The law states that the entropy increases with time.You can differentiate time by considering the entropy.if the entropy is increasing than you are moving forward in time.

    The psychological arrow can be understood by memories.either human or computer.you remember things of the past.why is it so?it is because we are moving forward in time.the psychological and the thermodynamic arrow points in the same direction.

    I know this answer might not satisfy you and I maybe wrong and so I encourage the experts to correct me if I am wrong.

    For better understanding read 'the theory of everything' by Stephen hawking.it is given under the heading of the arrows of time.
  8. Oct 7, 2015 #7
    thanks for all the answers,
    I was thinking there might be something philosophical because time is a slippery area of physics and I'm pretty new to some of these concepts.
    So from what I've read, yes time does pass this fast, at least psychologically. A second is a second, always, but there are complexities relating to how curved space-time is.
  9. Oct 7, 2015 #8
    Philosophy is the subject made by humans.If we would not have come than it would never have existed.

    According to me the only subjects which were there before us was science.and studying it will give the answers to the universe.thats why I love it sooo much.
  10. Oct 7, 2015 #9
    So are the math and physical laws we use to predict physics. They are required for a scientific theory, however philosophy is practically irrelevant in physics and therefore frowned upon in this forum.
  11. Oct 7, 2015 #10


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    Two important classes of (ideal) clocks: frame-of-observer clock (aka "my clock") and every other clock. Your (ideal, perfect) clock will NOT be measuring the same as mine in the sense that if we synchronize them to zero (or any other time point) then they will immediately begin to "drift" apart - depending on the relative motions you and I experience and the gravity we are under. They have been able to show that one clock which was 1 foot lower than another (in Earth's gravitational field) ticked more slowly...or saying the SAME thing: the clock a foot higher ticked faster. Each was correctly ticking away the time it was experiencing and yet their read-outs slowly drifted apart. We call the time a clock attached to something else (a clock which is NOT "my clock") "Proper Time". Proper time is almost always different from the clock(s) in an inertial frame of reference. This is what special relativity is about, the mixing up of space and time, velocity and the speed of light. General Relativity adds energy and mass (gravity) to that mix. That is, in order to compute the proper time of an object in the real world (the world of GR), we not only need to know its speed and accelerations, but also need to know its energy as well as the masses around it. Anyway, it is always "bad physics" to claim time "slows down" or time "speeds up". It is "bad" because it fails to distinguish between observer and observed. The observer's time NEVER slows or speeds, while the observed's time almost always does (but in the world around us, the effect is so small that you should be able to ignore that and never run into problems (unless you're a physicist dealing with the very fast, the very far, the very large, or the very energetic).
  12. Oct 7, 2015 #11
    thanks ogg,
    So i'll look at this from a different perspective: say we humans could process information so fast the we could observe quantum events happening. The question is, from our perspective, would we observe more time? So in a conscious mind is experience of time related to processing speed? or not.
  13. Oct 7, 2015 #12


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    Staff: Mentor

    Our perception of time may change if our processing speed was drastically increased, but the rate that time passes for us would remain unchanged.
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