Timekeeping on Mars

Sol is a term for the period of rotation of Mars to the sun, so for a Martian day. The duration of this day - and - night cycle (one day) is 24 hours, 39 minutes and 35.244 seconds.

In contrast to the sidereal rotation period of Mars - its rotation with respect to the fixed stars - which is only 24 hours, 37 minutes and 22.66 seconds, the solar day lasts a little longer, as he himself nor by its orbital motion around the Sun for something more must turn on its own axis.

A sol is mainly used in English, for example by NASA scientists as a measure of time to plan the use of the Mars Rover.

Future / Science Fiction

In view of a possible Mars colonization raises the question of how to transfer the Sol on watches. In the science fiction series Mars trilogy by Kim Stanley Robinson Mars the settlers use underground classic watches which stand at midnight for 39 minutes and 40 seconds. This creates a kind witching hour, which compensates for the time difference to the earthly day.

Another, more practical design delivered in 1988 David Powell with the Davidianischen Martian calendar. Then the clocks run slower than plain ground, so that its Mars hour hand walked around twice by a sol. So corresponds to 1 Mars 1.027 seconds earthly seconds, 1 minute 61.62 Mars earthly seconds and 1 hour 61 minutes Mars and 38.968 seconds on Earth.