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Does time have a speed?

  1. May 18, 2012 #1
    Last night i was in my room thinking about time, and a few questions came to mind. Im 14 and tried asking my science teacher, but he could not answer them and suggested posting them on a website like this. List of questions:

    It has been proven in tests that the faster you move, the slower time goes for you. As in if i were to travel going at the speed of light for say (and this is just an example, not accurate) 7.5 years away and 7.5 years back going the speed of light, when i arrive back it would have been 3000 years on earth, but only 15 years for me. So i was wondering why does this happen? So my first question is: Does time have a speed? In other words, is the reason for this happening because time has a defined speed and the faster you go the more you "match" the speed of time causing you to be ahead of still or less fast objects but still be behind time itself? I imagined it like this: 3 runners having a race. The finish line would be the end of the "race". The first racer would be regular still and slower objects. The second would be you going the speed of light. The third object would be time. Time is in the lead and always will be. But the faster you go, the less differnce between your time and times time. Just comment if you need me to explain this further, its not easy. This brings me to my second question. If time has a speed, that would mean its moving. If time was moving, that would mean it has energy. If it DOES in fact have energy, could we harness this seemingly infinite abundance of energy? For my last question/theory and also my most shaky and unsure one, it is that if time is energy, does that mean that time needs energy to happen? and does energy need time to happen? Or could time really just be non-existant. Could time just be energy doing work?

    It would make my day if someone could answer these questions that have been bugging me for the whole day. Google dosnt seem to help much /:
     
  2. jcsd
  3. May 18, 2012 #2
    The best simple and qualitative explanation I've heard about this is to imagine that we are always traveling through space-time at the speed of light, [itex]c[/itex]. That is, motion through both space and time has to add up to that number, so motion through space slows down your motion through time, and vice versa. Therefore, if you are traveling at the speed of light through space, you experience no time at all! This is what we believe to be true about objects that travel at the speed of light.

    But you don't want to think about time has having a speed; all objects have their own conceptions of time, and time itself is not really thought of as a separate entity, for exactly that reason. It sounds like a good way for you to get acquainted to this material is to read an introductory text to special relativity. You will have difficulties understanding the concepts involved if you try to learn it piecemeal.
     
  4. May 18, 2012 #3
    I dont really understand what your trying to explain but ill catch up on some special relativity books and it should make sense, thanks for the suggestion!
     
  5. May 18, 2012 #4

    K^2

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    To expand/clarify on what Dan said, Time is just a coordinate. Time doesn't move. You move through time as you move through space. When you are at rest, you move through time at rate c. When you travel through space as well, that rate changes.
     
  6. May 20, 2012 #5
    Well...time is relative depending on position of the observers.If you travel with a velocity close to that of light, the period of your clock would be longer than a reference clock(it would take more "time" for your clock to tick one second than the reference clock).well that is time dilation given by special theory of relativity.Regarding aging,i personally donot think time dilation would affect it at all.Aging occurs due to mutations(changes) in the genes,and they donot do so by looking at your clock...anyway that's my point of view...also i might be wrong.
     
  7. May 20, 2012 #6
    what actually happens is that if you speed up from rest to a high speed with a clock and match the time taken for one tick of your clock with your counting in your mind ... you'll find that the ticks of clock are exactly at same rate .... but if you reach back to the place you started and ask the person static there you'll find difference in the time of the two clocks (initially they must be synchronized )
    your imagination of time in race is wrong as time doesn't moves ......
    perform this experiment in your mind-
    take a flexible black rubber sheet ...... make a large number of blocks on that sheet ...... each block represents time ..... like block 1 - 00:01 AM block 2 - 00:02 AM and so on ...
    wen you stand on this sheet at a fix position, you stand on that time (and for you the time will stop if you are perfectly still there) ......... but wen we r still (like you must be now while reading this) ... we move on with speed of light and hence time looks to move.
    now suppose you keep a massive object on that sheet .... the object will stretch the sheet and the boxes of time you made will become a bit longer (and hence will cover a larger area ) near that massive object.
    then the time will be same over a larger position near that object as compared to other time boxes.....
    now when we gain speed (and hence energy) we gain mass ... as per equation E= mc^2
    as we become massive we stretch this sheet more and difference in time is observed.
    our universe is actually this 3 dimensional sheet.

    ...
    well you are too young to know and understand about this but even i was same in my 14's and now after 4 years of it , I'm explaining it to you.
    keep it up.
    post your droughts if any...
    Zubeen.
     
  8. Jun 24, 2012 #7
    dilsfunspot, I'm 62 and a lay reader in physics for some time, with questions like yours about relativity. I think Zubeen has a good response. The one thing I wanted to tell you, and he has said it above, is that time does not slow down as we approach light speed; that view is too simplistic. It is, as Zubeen has said, that time remains the same for us at any speed, as does the speed of light relative to us. Our clocks and our activities seem to progress perfectly normally...to us, within our frame of reference.

    But to the observer we left at our point of origin, from whom we have accelerated faster and faster away, nearing the speed of light, our time seems to move slower than their (the unmoving observer's) time. Now this is a thought experiment, and I'm not at all sure that there would be any way possible for the stationary observer to actually observe the activities aboard the fast-moving starship we envision in this imaginative experiment. (If you filmed the activities aboard ship, including the movement of the clock hands, and then transmitted what you filmed at light speed to the stationary observer--well, I don't even want to try the math on how long it would take to receive the film or how attenuated the film might become, but--the film would display perfectly normal time passage because the camera is also aboard the ship and in the ship's frame of reference regarding space-time.)

    I like Zubeen's image of a rubber sheet marked for moments of time to illustrate how massive objects and the mass increase from motion can increase the size of such moments of time. I think your image of the race against time and not being able to race faster than time has some good points to it, and I think I can see where you're coming from. Zubeen, if I may speak for him (and I probably should not), would probably tell you that in such a race, it is better to imagine time as the race track rather than one of the racers. Indeed, time does not move. Instead, we move through time, like horses on a race track, and Lightspeed is the name of the odds-on favorite; the rest of us will be in the pack as far behind Lightspeed as the pack following Secretariat to the tape at Belmont. :-)

    Back on subject, remember that time is a conceptual contrivance of our own device; it is man-made. It is how we measure change within our frame of reference--e.g., by comparing all events to a standard of measure like a clock or calendar. The reality of time is not the measure, but the event, the countless intermingling changes that make our world constantly different. If time has a speed, it is the rate at which such changes occur, for example the rate at which a photon of light can change its location or the rate at which a cesium atom may experience nuclear degeneration (or the rate in which a mechanical cog in an elaborate mechanism can move one space and change the location of a second-hand by one second). My wife tells me that muons change to electrons in 2.2 seconds (according to a post she read), but accelerated muons have been measured to last up to 30 times longer before changing into electrons. You see, we measure the muon from the frame of reference of the stationary obervers. If we could put a clock on the muon, we would find that it measured only 2.2 seconds before the change occurred. But the change is the thing.

    That is the real speed of time.

    Samm
     
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