[EMAIL PROTECTED] wrote:
However if decimal time has 10 decimal
hours/day, then 7:32 AM (07:32) would be 7.5333 hours or 3.1389 decimal hours.
3.139 decimal hours = 0.31389 days. I call decimal days decidays. I call
decimal minutes millidays. I call decimal seconds centimilidays
I can't understand how these various confusing time units are related to SI metric. In SI metric, the basic time unit is the second (defined in terms the time for oscillations of atoms in a particular kind of atomic clock). It is not sufficient merely to identify how many of one of these new units is equal to another one of these new units. At some point you have to identify how big one of the units is by relating it to a physics standard (or a previously defined unit, such as the SI second, which has already been related to a physical standard).
Gavin seems to be trying to base his entire system on days as the fundamental unit. Unfortunately, all days are not of equal length. Even the average day (the so-called "mean solar day" of earlier times) is not sufficiently stable to base our entire time system on it. (Even the average day is changing.) That is why SI does not define time units in terms of the day, but instead in terms of the period oscillation of certain atoms in atomic clocks. It uses those oscillations to specify how long a second of time is.
Fundamentally, I ask Gavin whether the "day" he is using is the day of 24 hours with each hour being 60 minutes and each minute being 60 seconds where those seconds are the SI seconds. Any other definition would require changing the definition of the second (making the second a different length of time than it is now). That would have enormous negative consequences for all the rest of SI and all measurement sensitive activities on earth (all science and engineering and medicine etc.) Indirectly, Gavin seems to be proposing a second to be ten to the -5 days (1/100 000 of a day). The current SI second is 1/86 400 of a day. Such a change in the second (a 16% change if that is what Gavin really means) us totally unacceptable.
And for what ...
For the introduction of a bunch of new, non coherent units like decidays and centimillidays (both of which violate other rules for prefixes in the SI system). The prefix "deci in SI means one-tenth, so a "deciday" should be one-tenth of a day, but Gavin says that a deciday equals a day. Gavin suggests using the term centimillidays in contradiction to the SI rule that prefixes are not to be used in combination. SI rules require the use of the nearest single prefix instead. And if he is calling the decimal day by the name "deciday" then why isn't his smaller unit called the centimillideciday? All this is complete confusion.
I am anxious to promote the use of the SI metric system in the USA and anywhere else that it is not currently in common use. I am NOT interested in discussing wholesale changes in SI that would destroy the simplicity and usefulness of that system.
Regards, Bill Hooper Fernandina Beach, Florida, USA
