[quizzical72 (OP)]

I've read that the Sun moves one degree per day from the viewpoint of the Earth, but what about on Mars? The Martian year is almost twice the length of the Earth year due to its orbit around the sun.

Days on Mars are almost the same as on Earth and are measured in sols. However, according to the sources I've read (Planetary dot org), the times of the week or month would be delineated in "Ls" or solar longitude degrees, with the summer soltice an L-90 (I think).

Can anyone explain how this would work in more detail?

[ahillconti]

 How long is a day on Mars equivalent to earth?

[evan_au]

A Mars solar day is 24 h 39 m, or 3% longer than an Earth day.

I doubt that an astronaut would notice the difference - unless they were talking to Earth, in which case a regular daily meeting would keep changing start time by 40 minutes every day..

...the time of year is shown as the number of degrees from the northern vernal equinox, and increasingly there is use of numbering the Martian years beginning at the equinox that occurred April 11, 1955.

From: https://en.wikipedia.org/wiki/Timekeeping_on_Mars

[quizzical72 (OP)]

Thank you for your responses. But does the Sun move one degree per day on Mars like it does on Earth? I couldn't find the answer to this question easily.

[Halc]

Thank you for your responses. But does the Sun move one degree per day on Mars like it does on Earth? I couldn't find the answer to this question easily.

By definition, the sun moves not at all (on average) from day to day, but it does move about one degree per sidereal day (of which there are ~366.¼ per year).  So if Mars has 640 sidereal days per Martian year, then the sun moves 1/640th of a circle (a bit over half a degree) per sidereal day. Per actual day, it doesn't move at all, again by definition.

On Mercury, despite it rotating the same direction as its orbit, the day is longer than its year, but the sidereal day is shorter that its year. The sun crosses the sky the wrong way, and stops its motion altogether and even moves backwards a little bit (same time every year) before continuing on its normal way, a funny sight to us, but just normal for anything there.

[JaffH_iii]

Thanks, very informative