On Sat, Apr 11, 2020 at 5:14 PM <mix...@bigpond.com> wrote: > > > Note that our perception of the flow of time and even our measurement of > it is based on processes which may vary in > speed. IOW if the fabric of space time changes, e.g. in a gravitational > field, then the processes upon which our clocks > are based may speed up or slow down, but this doesn't *necessarily* imply > that time itself is flowing faster or slower. > It may be, but we have no object means of telling the difference. IOW our > temporal "yardstick" may change in length in > some situations. A clock can run fast or slow without the actual passage > of time changing. > > I agree. For example an increase in ambient temperature can change the period of pendulum clock by increasing the length the swing arm. However, we don't say time slows down just because it got warmer. In the 18th century pendulums were designed so as not to be affected by temperature. Although we can't block the affects of gravity on a clock, we can make sure a clock at the surface of the Earth keeps the same time as a clock in deep space by systematically adding time to the measured time on Earth.
Harry
