Martian Semi-Metric (24*10*1000) Clock
This is an attempt to visualize a different kind of clock for Mars
than the standard stretched-24*60*60 proposal. The stretch is actually not
too bad, since there are 24 hours, 39 minutes, 35.2 seconds in a mean solar
day on Mars. (That's 88775.2 seconds, or 2.749% longer than an Earth day.)
In this clock proposal, there are still 24 hours in the day, so that a day
may still be divided conveniently into shifts. But the hours are divided
into 10 parts, probably not called "minutes", which is further divided into
1000 parts, probably not called "seconds"*.
(Note: the Martian Date is according to the Darian Calendar, in numerical
format, as I am not fond of Tom Gangale's sense of naming. His otherwise
excellent calendar can be found
here.)
Advantages:
- Convenient units:
- If you watch the applet, you notice that the metric "seconds" field clips
along at a comfortable pace, maybe a little fast, at about 0.37 earth
seconds each. It's about as fast as you can count, if you talk fast. (No
"Mississippi" on Mars.) It's fast, and yet not fast enough for blur, as with
tenths-of-a-second on Earth. I find this very appealing.
- The metric "minutes" are about 6:10 earth-minutes long. The
5-minute interval has proven to be such a comfortable length of time, that
we rarely tell time in smaller intervals here on Earth, and we usually even
take the extra effort to round to the nearest 5.
- Efficiency:
It saves a little bit of writing-space and speaking-time:
"12:30" becomes "12:5" ("twelve-five").
- Less confusion:
- "12:5" is clearly distinguishable from an Earth time (such as "12:30"),
which is basically the same argument usually given for not naming Martian
months January, February, March...
- One is also not quite as tempted to call
the smallest units "seconds", which would cause confusion with the SI unit
that would naturally still be used among scientists on Mars.
- On Earth, 4:10 could mean
either 4 hours 10 minutes, or 4 minutes 10 seconds. But with this Metric clock,
you can clearly distinguish them by number of digits, since each field has a
different number of digits.
- It's easier to add and subtract time intervals in base 10 than in base 60.
Disadvantages:
- With 24*60*60, you basically knew that 10 minutes on Mars was just 2.7% longer than
10 minutes on Earth. Time on the scale of minutes might reasonably be
discussed between Martians and Earthlings. With Metric time, it's hard to be
constantly multiplying and dividing by 6 for minutes, and 0.37 for
seconds. The only halfway-redeeming quality is that if you are forced to
use a calculator, you will usually get a more accurate number.
- It lacks familiarity, besides the 24 hours.
*
Even with a 24*60*60 system, there is a need to avoid calling the units by
their Earth equivalents. Witness the failure of Mars Observer due to a
confusion of English and Metric units ... units that aren't as easy to confuse.
Here are some naming suggestions:
tal, the smallest unit of time in Edgar Rice Burroughs' classic Martian
sci-fi tales.
millitik, where the "minute" unit is a "tik" and the "Martian hour" is
a "dekatik".
sixth, because the unit is about 1/3 of a second... :-)
Addendum
It has been brought to my attention that there is a slight modification
of this scheme that has an interesting advantage: fitting with the earth second.
The 'tik' unit is 369.897 seconds long. If we standardize it to exactly 370
standard seconds, there will be 24 hours, 40 minutes in a day, overshooting
the actual Martian mean solar day by just 24.8 seconds. This could be
corrected by two (sometimes one) 'skip tiks' (spring forward) per month
(assuming 24 months in a Martian year). That would be a loss of 12 minutes,
20 seconds at the end of every 4 weeks.
It sounds like a worthwhile compromise.