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The majority of these terms are chosen as contractions of the longer terms which use the adjective "areological." Hence, a dar is a "day areological", or Martian day. The terms are also chosen to preserve the initial letters used to express Terran times, allowing Martian times to be expressed with the usual single letter indicators d, h, m, and s. A future Interplanetary Standards Organization can sort out the problem of choosing symbols to distinguish Terran hours from Martian hars. |
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You can now describe the general characteristics of a Martian clock. It will count in the usual fashion from 00:00:00 (midnight) to 23:52:66. At this point, however, it will not roll over to 00:00:00 again, but proceed to 24:00:00, 24:00:01, and so on until 24:52:66, when it will then roll over to 00:00:00. It is difficult to imagine an analog clock with this capability, so Martian clocks will be digital. They can be similar to Terran clocks, but the count logic will need to detect the 24:52:66 pattern, rather than 23:59:59, for reset. |
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9.13.2.1.8.4
Adjusting the Clock |
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There is one additional wrinkle to this scheme, of course. The dar actually consists of 887,755.23 seconds. In order for the clock to keep time with the calendar, a leap second rule will need to be instituted within the clock. This problem does not occur on Terra, because the day is defined as an integer number of seconds. The necessary rule can be worked out in the same fashion as the calendar rule. |
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The error of 0.23 seconds is one second every 4.347826 dars. This result gives us a choice of two rules, assuming that you want to correct for errors greater than one second. You can either add one second to the official clock every five dars, in which case the official clock runs slightly behind, or every four dars, in which case the official clock runs slightly ahead. In either case, an additional correction rule is required. |
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I'll look at the two cases in more detail. The first case is that of adding one second every five dars. Because the discrepancy between the actual clock and the official clock is 0.23 s/dar, the discrepancy amounts to 23 s in 100 dars. In 100 dars, the rule will add (100/5 =) 20 s, which is three seconds short of the required total. These three seconds must be allotted among the total by a second rule. This rule can be expressed in two equivalent ways: |
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on dars 35, 70, and 100, add one additional second, or |
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if the calculated error on a fifth dar is greater than 1.0, add one additional second. |
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