What Time Is It On Mars?

Time is tricky, and it’s only gonna get worse when we become a multi-planet species. Fortunately, [Folkert van Heusden] has a clock ready for what may be our second home with the Mars Clock. This simple build shows the current time on Mars, using the Martian calendar that NASA uses for their planetary probes.

This calendar, called Mars 24, was designed by [Michael Allison] of NASA back in 1998, and is used by the current batch of Martian probes. You can’t just use an Earth clock on Mars because a Martian day is 24 hours and 39 minutes. Instead, [Michael] created a new calendar based on the rotation and orbit of Mars that also allows you to calculate sunrise and sunsets, which is vital for a probe that uses solar power. It is based on the same breakdown of time, with 24 hours, 60 minutes and 60 seconds, but each of these is slightly longer than the Earth equivalent.

[Folkert] tool the example formulas that NASA themselves provide for calculating Mars 24 time, and wrote an Arduino program that converts Earth to Mars 24 time. This then drives an LED ring that indicates the hour in (appropriately enough) red, the minute in green and the second in blue. This is then mounted on a wooden plate and case that he created with Makercase, a neat site that creates plans for wood laser-cut cases.

It’s a neat, simple build overall, although I would like to see one addition: a switch to go between Earth and Mars time. And perhaps a heat ray attachment that will assist the inevitable victory of our new Martian overlords.


24 thoughts on “What Time Is It On Mars?

  1. I like this, I’ve made a similar clock (as I’m sure many have) for terrestrial time, but with a 24 hour ring in the middle.

    The loop code in the Arduino sketch ends with a delay(1000), that should probably be either much faster or a correct subdivision of the Martian second measured in Earth seconds.

    I don’t think the bare LED ring looks great mounted on the wooden panel, it could do with being behind a translucent diffusion ring.

    1. I think it has something to do with Elon Musk lobbying the Martian High Parliament.
      They were all set to enact Time Zones, but he’s telling them it could affect future trade and off-world immigration.
      But then, they were considering Fibonacci based zones.

  2. I’d guess there aren’t right now. The only real reason we need time zones is so that us squishy humans can all agree that 7:00 AM is breakfast and so forth. Probes and rovers don’t care about that.

  3. On Earth, the desire for Daylight Saving [not Savings] Time (DST) arises when people want to have more daylight in the summer evenings to spend outdoors, but want the daylight in the wintertime more evenly spread between the morning and afternoon.

    The demand for Martian DST will depend on how many of the immigrants from Earth will want to bask outdoors during their Martian summers.

    Certainly there will be a difference in the amount of daylight during Martian summers and winters. Mars’ axis tilt is 25 degrees, slightly more than Earth’s 23.5 degrees tilt.

  4. Well I guess it’s alright but can it tell me what time it is on Uranus? Well now that that’s out of the way, I like a Martian clock but what I’d really like to see is a mechanical Martian Clock, maybe 3D printed, now that would be cool.

    1. Based on how this clock has been implemented you only need to change the length of a second, so basically every mechanical clock can be a Martian clock. If it has a pendulum you need to lengthen the pendulum slightly, if it has a balance wheel you need to relax the spring tension slightly.

      1. You can tell martian time on earth with a lengthened pendulum, but I believe you’ll need a much shorter one to tell martian time on mars with a pendulum based clock… “g” is different.

  5. Just one query that no-one has addressed. How are you going to correlate Martian and Earth time? 09:00 on Mars on Monday may be the same on Earth if we can agree a sync point but on Tuesday, 09:00 on Mars will be 09:39 on Earth and within a few months we’re looking at days being the difference. (I know one of you will be busy making the correct calculations, so I’m not going to bother).

    1. I think the astro community is still trying to figure out how to define “months” within a Martian year.
      (Two moons, low orbits, faster revolutions.)
      Otherwise, you could make the Martian clock with a 24 hour dial, and have a counter increment for each Martian day,
      and compare that with a Terran clock/counter originally synced to each other.

    2. It’s like the tides. They move around with the moon, so they don’t come up at the same time every day. But we seem to care about days as defined by the sun.

      If you also care about the sun as seen from Mars (solar power, biorhythms) then they need to be set differently.

      I can see the ad copy now: “Come to Mars, and enjoy our slower pace of living!”*

      * Technically, 2.71% slower.

  6. Nope!

    Nice build but if we ever have people living on other worlds I don’t think they will measure time this way.

    Seconds are a SI unit. SI units are al interrelated in scientifically meaningful ways. If you change the length of a second you change everything.

    My best guess is they will use a different number of seconds in a minute, that along with some crazy leap seconds.

    Then again.. when you are stuck inside a habitat all the time anyway.. might as well just go stick Earth time.

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