Results 1 to 9 of 9

Thread: Time and Relativity.

  1. #1
    Join Date
    Jul 2016
    Posts
    12

    Time and Relativity.

    "Time is what a clock measures." -

    I am sure we are all familiar with Einstein's famous definition of time; but what does it mean?
    Every clock measures some sort of change, whether it is a clock’s movement(pendulum/subatomic changes) or part of the clock’s environment(sundial).

    In an environment that is totally inert - (In which nothing is changing, even at the subatomic level) would any time pass? If nothing is changing, there is nothing for a clock to measure, so any clock would be 'stopped' or 'frozen in time'.

    Place a clock in such an environment and time would pass because of the changes taking place within the clock - the clock's 'movement'. It will measure time generated by the changes that are part of the clock.
    So is time generated by change?

    All changes are governed by scientific laws; therefore time must be generated at the same rate in identical clocks subject to the same environmental conditions, (Einstein's first postulate)
    and, based upon the constancy of the speed of light c, (Einstein's second postulate) the time measured for identical changes, in identical conditions, obeying identical scientific laws, must be the same in any inertial frame of reference. So how does a clock moving inertially run slow?

    Because of Relativity.

    Relativity, the viewing and measuring of mechanical processes in system, K', moving relative to observers in system K.

    It is because of the motion of the clock's System, K', relative to the observer's system, K. A clock at rest in its own frame measures proper time when read from its frame, while an observer in another frame relative to which the clock is moving, measures coordinate time for that moving clock.

    There are then two measures of the time read on the clock in a system. Proper time measured by the system’s own, local, clock at rest in that system, K', and Coordinate time measured against the local clock in an observer’s system, K, relative to which the system K’ is moving.

    The Spacetime, or Invariant, Interval between two events is the same for all observers. It is the proper interval, read objectively by an observer for whom the clock is moving using the 'rods and clocks' of the moving system; or, by using the 'rods and clocks' from the observer's own system, they may read the moving clock subjectively - adding (by vector addition) the transit time of the measured System K', relative to the observer's System K, to give the coordinate time.

    Coordinate Time is a Subjective measure made from another system, K, using the clock in system K.
    Proper Time is an Objective measure that can be made remotely from anywhere, by any observer, using the rods and clocks of the measured system, K’. An objective measure takes no account of the location, nor the motion, of the observer.

    Surely one of the main reasons for Einstein’s Theories of Relativity, was to recognize that measurements are fundamentally Subjective.

    Definition of Time

    Time is generated by intervals in processes of change.

    Time is a measure of the duration of change. Time is generated by any process of change.

  2. #2
    Join Date
    Mar 2007
    Location
    Falls Church, VA (near Washington, DC)
    Posts
    7,150
    Quote Originally Posted by TyroJack View Post
    "Time is what a clock measures." -

    I am sure we are all familiar with Einstein's famous definition of time; but what does it mean?
    Every clock measures some sort of change, whether it is a clock’s movement(pendulum/subatomic changes) or part of the clock’s environment(sundial).

    In an environment that is totally inert - (In which nothing is changing, even at the subatomic level) would any time pass? If nothing is changing, there is nothing for a clock to measure, so any clock would be 'stopped' or 'frozen in time'.

    Place a clock in such an environment and time would pass because of the changes taking place within the clock - the clock's 'movement'. It will measure time generated by the changes that are part of the clock.
    So is time generated by change?

    All changes are governed by scientific laws; therefore time must be generated at the same rate in identical clocks subject to the same environmental conditions, (Einstein's first postulate)
    and, based upon the constancy of the speed of light c, (Einstein's second postulate) the time measured for identical changes, in identical conditions, obeying identical scientific laws, must be the same in any inertial frame of reference. So how does a clock moving inertially run slow?

    Because of Relativity.

    Relativity, the viewing and measuring of mechanical processes in system, K', moving relative to observers in system K.

    It is because of the motion of the clock's System, K', relative to the observer's system, K. A clock at rest in its own frame measures proper time when read from its frame, while an observer in another frame relative to which the clock is moving, measures coordinate time for that moving clock.

    There are then two measures of the time read on the clock in a system. Proper time measured by the system’s own, local, clock at rest in that system, K', and Coordinate time measured against the local clock in an observer’s system, K, relative to which the system K’ is moving.

    The Spacetime, or Invariant, Interval between two events is the same for all observers. It is the proper interval, read objectively by an observer for whom the clock is moving using the 'rods and clocks' of the moving system; or, by using the 'rods and clocks' from the observer's own system, they may read the moving clock subjectively - adding (by vector addition) the transit time of the measured System K', relative to the observer's System K, to give the coordinate time.

    Coordinate Time is a Subjective measure made from another system, K, using the clock in system K.
    Proper Time is an Objective measure that can be made remotely from anywhere, by any observer, using the rods and clocks of the measured system, K’. An objective measure takes no account of the location, nor the motion, of the observer.

    Surely one of the main reasons for Einstein’s Theories of Relativity, was to recognize that measurements are fundamentally Subjective.

    Definition of Time

    Time is generated by intervals in processes of change.

    Time is a measure of the duration of change. Time is generated by any process of change.
    What, if anything, in this post is contrary to mainstream theory?

  3. #3
    Join Date
    Jun 2006
    Posts
    4,344
    Problem #2 with the OPs idea is that there is no place in thi universe without contiuous change. The sea of neutrinos and random quantum evebts ensures that.
    I'm not a hardnosed mainstreamer; I just like the observations, theories, predictions, and results to match.

    "Mainstream isn’t a faith system. It is a verified body of work that must be taken into account if you wish to add to that body of work, or if you want to change the conclusions of that body of work." - korjik

  4. #4
    Join Date
    Aug 2008
    Location
    Wellington, New Zealand
    Posts
    3,190
    Quote Originally Posted by TyroJack View Post
    "Time is what a clock measures." -

    I am sure we are all familiar with Einstein's famous definition of time; but what does it mean?
    We need a source and context for that quote.

    Sir Hermann Bondi had a similar statement about measurements in "Relativity and Common Sense: A New Approach to Einstein" (1980):
    Time is that which is measured by a clock. This is a sound way of looking at things. A quantity like time, or any other physical measurement, does not exist in a completely abstract way. We find no sense in talking about something unless we specify how we measure it. It is the definition by the method of measuring a quantity that is the one sure way of avoiding talking nonsense about this kind of thing.
    This is fairly obvious. Physical quantities are abstracted in physics. The time on a clock is not the time coordinate in a Minkowski diagram.

    We could start with a universe containing just a clock, observe that time passes, take away the clock and note that no laws of physics change. There is still time. What changes is the ability to measure time.

    Quote Originally Posted by TyroJack View Post
    ...Time is generated by intervals in processes of change.
    The "intervals" part of that assertion does not follow. Clocks suggest that time passes continuously. We have not reached any limits yet in building more and more accurate clocks (smaller and smaller "intervals").
    Relativity explicitly states that time is continuous as is space. No matter how small an interval we look at in relativity, there is always a smaller interval.

  5. #5
    Join Date
    Jun 2006
    Posts
    4,344
    Aren't you just re-hashing your previous ATM thread? If not, what is different in this thread?

    https://forum.cosmoquest.org/showthr...tning-strikes)

    Link is above.
    Last edited by John Mendenhall; 2017-Apr-25 at 04:06 AM. Reason: add link to previous ATM.

  6. #6
    Join Date
    Jul 2016
    Posts
    12
    Quote Originally Posted by Reality Check View Post
    We need a source and context for that quote.
    I have seen numerous assertions in Wiki articles etc. claiming this is something Einstein said - possibly in his arguments/discussions with Henri Bergson a famous philosopher; but I have not pinned it down yet... Yet it does seem to be accepted as a common saying that is oft quoted...

    Quote Originally Posted by Reality Check View Post
    We could start with a universe containing just a clock, observe that time passes, take away the clock and note that no laws of physics change. There is still time. What changes is the ability to measure time.
    But that is exactly what I am saying. If there were a universe containing just a clock... time would only pass while the clock was there, for the mechanism of the clock would involve a 'process of change', which the clock measures in order to measure the time it is generating. If there were no clock, in a totally empty/inert universe no time would be generated. The laws of physics would still apply just the same and if anything were to change it would change according to the Laws of Physics and time would be generated according to those laws.
    I am saying that time only happens when something is changing.


    Quote Originally Posted by Reality Check View Post
    The "intervals" part of that assertion does not follow. Clocks suggest that time passes continuously. We have not reached any limits yet in building more and more accurate clocks (smaller and smaller "intervals").
    Relativity explicitly states that time is continuous as is space. No matter how small an interval we look at in relativity, there is always a smaller interval.
    Forget about intervals that word was not necessary...

    Time is generated by processes of change

  7. #7
    Join Date
    Jul 2016
    Posts
    12
    Quote Originally Posted by John Mendenhall View Post
    Problem #2 with the OPs idea is that there is no place in thi universe without contiuous change. The sea of neutrinos and random quantum evebts ensures that.

    True. But my argument is about the nature of time...

    It is that time is generated by change. Chnage is continuous and therefore time is continuous, which is what is experienced.

    Consider: time is experienced in any inertial frame of reference according to the same laws of Physics. Measured on a stationary clock by an adjacent observer this is proper time.
    Time measured in a frame of reference moving relative to an observer, has the additional process of change of the moving frame of reference. The time generated by the movement of the frame of reference is separate from and does not affect the time measured within that frame of reference; but to the observer of the moving frame, more time is generated. This additional time is added (by vector addition) to the proper time in the frame of reference to give the coordinate time measured by the observer.

  8. #8
    Join Date
    Oct 2009
    Location
    a long way away
    Posts
    9,648
    Quote Originally Posted by TyroJack View Post
    True. But my argument is about the nature of time...

    It is that time is generated by change. Chnage is continuous and therefore time is continuous, which is what is experienced.
    Change is varied and variable (depending on which change you measure and under what circumstances). Time isn't.

    In relativity, time is just a geometric dimension equivalent to those of space. This requires no change for time to exist.

  9. #9
    Join Date
    Apr 2006
    Posts
    1,584
    Quote Originally Posted by TyroJack View Post
    True. But my argument is about the nature of time...

    It is that time is generated by change. Chnage is continuous and therefore time is continuous, which is what is experienced.
    This is just a restatement of Mach's second principle:-
    "It is utterly beyond our power to measure the changes of things by time. Quite the contrary, time is an abstraction at which we arrive by means of the changes of things."

    E Mach. The Science of Mechanics. Open Court, 1960. p273

Tags for this Thread

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •