======================== CirgreeSys wrote:
That all depends on what you MEAN by metric time.A strong case would have to be made towards adopting a metric time. :What are the advantages of metric time. :What are the disadvantages of metric time.
Consider:
The day is a physical phenomenon (identified as the period between some daily event and the next occurrence of that daily event (sunrise or solar noon or some such event).
The day is NOT CONSTANT in duration.
There is no way that a precise definition of a basic time unit (like the SI second) could be defined in terms of the length of a day (even when averaged over some longer period of time).
The question, therefore is, how does ANY proposed so-called "metric time" define its basic unit? Without an answer to this question, no reasonable discussion can be conducted about the merits of any metric time scheme.
Any proposal to define new units or redefine old units must necessarily come AFTER it has been decided how to define the basic unit upon which all the other units in that system are to be based.
QUESTION: How many seconds should there be in a day? ANSWER: That depends on how big your second is. Define your second.
The most recent proposal seen here for "metric time" defines the second as 1/(100000) of one day. As noted above, the day is not constant. Thus, the above definition of a second gives us a NON-CONSTANT SECOND. That is totally unacceptable.
SI does not seek to reconcile the unreconcilable here. Instead, it defines a second precisely, with no reference to the unreliable day length. Then, astronomers and others measure the day and find it is APPROXIMATELY 86400 seconds long - approximately, not exactly, and variable not constant.
If one wishes to define a time unit called a "day" as 24 hours of 60 minutes with each minute being 60 seconds long, it will be approximately equal to the length of a real day and GOOD ENOUGH for most practical daily purposes. The scientists can add a leap second or so every once in a while to keep things neat and the man in the street does not need to worry about it.
If you don't like the 24-60-60 scheme for dividing the 86400 second day into parts, then devise another one; BUT DON'T CHANGE THE LENGTH OF THE SECOND. You could divide the time unit day into parts that are 86.4 and 1000 as follows:
1 day (time unit) = 86.4 kiloseconds, 1000 seconds = 1 kilosecond.
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More discussion is possible but I promised myself (and you) I'd quit before this got even longer than it already is.
Regards, Bill Hooper Fernandina Beach, Florida, USA
