Mars Civil Calendar Poser

[GeeKay]

Having stumbled upon Wikipedia's article about the Darian Calender intended for use on Mars, I'm interested to know how this calendar corresponds with our own one here on Earth. More precisely, if the first day of the Martian year begins on Sol 1 in the month of Sagittarius (warning: this itself is very much a stab in the dark) does this coincide, temporally speaking, with our first day of the new year - due allowances made for the smallish, if variable time-lag existing between Earth and Mars? Or am I barking up the wrong planet?

 

Many thanks

 

https://en.wikipedia.org/wiki/Darian_calendar

[Janus]

The Darian calendar starts on the Day of the vernal equinox for Mars (the first day of spring in the Northern Martian hemisphere.) this will occur when the Sun is in(or near) Sagittarius. This will not coincide with any fixed date on the Earth calendar as Mars' orbital period and thus its calendar year is some 687 Earth days long. Thus if the Martian new year occurs on any particular Earth date, the next Martian new year won't happen until 6 weeks shy of 2 years later by the Earth calendar( If by chance the first Martian New year occurred on Jan 1, 2020, the next Martian New Year would occur in the middle of November of 2021).

[GeeKay]

Yes, I think I've got that. I guess then there's no reason why the calendars of both planets should coincide in any particular way.

[imatfaal]

Yes, I think I've got that. I guess then there's no reason why the calendars of both planets should coincide in any particular way.

 

 

There are lots of theories about where planets would form given an almost homogeneous protoplanetary disc and one disturbance - you can make up models that would put all the planets at orbits which are in a form of resonant series; whether this would ever give radii that would give a regular coincidence of calendar who knows. Some of the gaps on saturn's rings are because there is a actually moon in there clearing out the ice particles; but other rings are there because moons both interior and exterior to the gap combine to clear a path at a distance through gravitational interaction. It is not hard to extrapolate that idea to the dust grains around our nascent sun.

[swansont]

Yes, I think I've got that. I guess then there's no reason why the calendars of both planets should coincide in any particular way.

 

 

There could be a reason. Planets can have orbital resonances, but we are not resonant with Mars. We are close to a resonance with Venus, so that there is close to a coincidence on short time scales

https://en.wikipedia.org/wiki/Orbital_resonance