What is the smallest practical unit of time?

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The discussion centers on the concept of time and its smallest practical unit, sparked by the idea that time has no directional preference. It emphasizes that time is defined by changes in the universe or a reference frame, with physical changes marking the passage of time. The conversation acknowledges Planck time but suggests that practical measurements of time, like those from clocks, are more relevant. The thread concludes by noting that philosophical inquiries about time may not be suitable for the forum. Overall, the focus remains on the relationship between time and measurable changes in the physical world.
DarioC
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I've been thinking about this general concept for months. It became relevant to me when I read in a science book that the "arrow" of time has no preference as to which direction it goes, back or forward. At least in a mathematical form.

So I began to think about exactly what is time. Finally I reduced my question down to "what is the smallest unit of time in a practical sense?"

My logic became: time is represented by a change to the status (of the universe or local reference frame or other) from the "instant" that frame changes as to what physically exists now to what exists later.

My reasoning is that time is always measured by something changing. It may be the tick of Big Ben, or the rise time of a cycle of the frequency of an atomic clock, but it is always a physical change that defines time. The universe is one way now and then it is different, and there ain't no going back. I rather like the concept, it is a amusing thing to think about.

And yes I have heard of Planck time.

DC
 
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Time is what a clock measures, just like distance is what a ruler measures. Anything beyond that is philosophy and inappropriate for PF. Thread locked.
 
I do not have a good working knowledge of physics yet. I tried to piece this together but after researching this, I couldn’t figure out the correct laws of physics to combine to develop a formula to answer this question. Ex. 1 - A moving object impacts a static object at a constant velocity. Ex. 2 - A moving object impacts a static object at the same velocity but is accelerating at the moment of impact. Assuming the mass of the objects is the same and the velocity at the moment of impact...

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