|PAGE 1||Churinga Publishing||v|
|Books and publications on the interaction of systems in real time by A. C. Sturt
Economics, politics, science, archaeology. 28 Oct 01.
PDF PRINTABLE VERSION
|The Timeless Universe||
|Footnote 2 - Observational Frameworks of Time
by A. C. Sturt cont.
Time cannot be measured by an observer except in relation to a succession of periodic events. The measured time is therefore related to the scale of those events. It follows that observed times measured on different scales may be different. For times to be meaningful, it is necessary to relate them to the scale at which they have been measured. The possible range of scales is as follows.
The UniverseAn observer looking at the infinite Universe from outside would see no discernible events, and therefore have no way of telling whether time was passing.
GalaxiesThe rotation of a galaxy provides a means of measuring the passage of time. However an observer cannot separate the time which elapses between events from any variations in the rates of rotation of the galaxy, say a periodic slowing and speeding up, which would affect the 'yardstick'. Nor could the observer separate out any variation in the 'yardstick' caused by movement of galaxy from which the observation was made.
Stellar Orbital TimeFor our particular star, the Sun, an Earth year is completed when the pattern of celestial bodies has returned exactly to the pattern at the beginning of the period of observation. There is no way for an observer at this scale to know whether this period is itself varying. Such variation would be confounded with the timing of observed events on this framework of time.
Diurnal TimeA day on Earth is defined as mid-day to mid-day, where mid-day is the highest point of the Sun in the sky. However, a clock calibrated over the period of a year shows that the time at which the Sun reaches its highest point occurs oscillates regularly about a mean value. Diurnal time contains all the variation inherent in the Earth's rotation on its axis and its orbit relative to the sun.
Atomic Radiation Emission TimeAtomic time is measured by observing emissions of electromagnetic radiation caused by the oscillations of excited atoms such as those of caesium. The second is now defined in SI units as the duration of 9 192 631 770 periods of the radiation corresponding to the transition between two hyperfine levels of the ground state of the caesium-133 atom. This number of observed oscillations of the caesium-133 atom corresponded almost exactly to the time-interval of a second measured by stellar orbital time.
Atomic radiation emission is homogeneous through time, and therefore space. It differs from all the other frameworks of observed time in that an atomic clock taken to any other part of the Universe would show the same interval of time, the same seconds. An observer could check that the yardsticks were the same by matching the pattern of light waves from the travelling clock with that obtained from local atomic time.
Thus atomic radiation emission yardsticks are independent of the framework of time; they are homogeneous through time, just as the velocity of light is homogeneous through time.
However, there is still no way of determining the simultaneity of events independently of a common observational framework of time, because light, and therefore time information, has to travel from a source at an event to an observer.
Nor is there any possibility that the number of atomic vibrations of e.g. the caesium-133 atom changes with time, because number is homogeneous through time. The atomic unit of time would have been the same number of vibrations at any time in the past, as long as radiation of the type described as atomic existed. This is consistent with the model of the Universe in equilibrium.
homogeneous time and space
but time intervals of events still scale dependent
|Copyright A. C. Sturt 23 October 2001||continued on Page 7|