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Why we always say that time is forward?

  1. Sep 3, 2013 #1
    I have a doubt.Don't know if there is any significance in asking this.But i would like to know the reason why we always say that time is forward?Does it mean that it is always continuous?Can somebody help me please?
  2. jcsd
  3. Sep 3, 2013 #2
    Time is relative but we perceive it as continuous at a consistent rate since we travel at a speed that is much slower than the speed of light. While we do not completely understand the concept of time (how it exists/what causes it) we do know that it is useful for practical applications to assume that our perspective of time is accurate for our everyday things. For example, if you're used to it taking 20 min to get to your friends house you have no reason to suspect that it will be that different (ignoring traffic or whatever), it will probably always take 20 min within our perspective of time.
  4. Sep 3, 2013 #3


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    Staff Emeritus
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    You are asking about the arrow of time. You might want to start by reading this:


  5. Sep 3, 2013 #4
    You can consider One Second as the duration of 9 192 631 770 cycles of radiations corresponding the transition of between two energy levels of the Caesium atom , which makes time forward .
  6. Sep 3, 2013 #5
    People casually say that time moves forward.

    When people drive down a road, the road moves backwards.

    When we "move forward through time", time is really moving "backwards"; time moves from the future to the past.

    But we can't see the future, we only know the past, so it is more like we are driving down a road but facing backward only looking out the back - that makes the direction of time appear to correspond to the flow of the creation of the past, that we can see.

    The whole thing is kind of confusing...
  7. Sep 4, 2013 #6


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    That's because people keep trying to make time into something it's not.
    Time does not flow, move, or anything else, just like space does not. No one ever says "wow, look how fast space is moving", it's always how fast we are moving through space. (By which I mean relative to whatever chosen frame of reference) It boils down to the simple fact that, as measured by a clock, we continually move through time in a single direction. We never observe clocks to suddenly run backwards or anything.
  8. Sep 4, 2013 #7
    And time by definition cannot even run backwards because as every particle in your body is at a given position right now in this very second you are reading this the very next they will be in a different one and you just cannot get back the previous one. It's like smoke from a chimney every next one will be little different than the previous one , as they expand and go further to mix with the surrounding air you cannot get back their previous state and form.So we say time has passed.
  9. Sep 6, 2013 #8
    So does it mean that everything in this universe is preplanned?How can we think about past and future then?actually i didn't mean to point it as past and future.But to make clear i should do that.Since it is made a point that we always relate the frame with some other frames,how future and past can be thought of?Do there exist anything like future?
  10. Sep 6, 2013 #9
    I don't think anyone made the implication that everything in the universe is preplanned. Depending on your concept of time it doesn't always move forward and isn't always consistent for example entropy and the arrow of time. On the microscopic scale there is the theory about antimatter and how that is normal matter in reverse (including time). I would say the future exists but in a different sense of what I think you're saying.
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