A planet with yearlong solar eclipse

[yh5598]

I want to write a story about a planet that has yearlong eclipse that how its natives and ecology adapt to this celestial condition. I am just wondering how realistic/feasible it is for some planet to have a moon in stable orbit producing eclipse for 1-3 years, every 70-100 years.

 

[Baluncore]

Welcome to PF.

At first, it seems to be impossible, since any moon would be orbiting about a planet with a different period to that planet about the Sun.

 

[yh5598]

Welcome to PF.

At first, it seems to be impossible, since any moon would be orbiting about a planet with a different period to that planet about the Sun.

Thanks for the reply! I am wondering if it's asking too much to have the reader accept this premise, since the focus would be on adapting the harsh environmental conditions a prolonged dark period would bring. Maybe the moon is bigger than the planet and less dense and orbits the planet super slowly. Maybe tweaking the orbit and eclipse time would make it more believable, but not entirely scientifically actuate.

 

[DaveC426913]

I am wondering if it's asking too much to have the reader accept this premise

In my opinion, that premise is simply too big to handwave without justification.

My suggestion would be to base your story on a plausible scenario and be flexible in how your world is set up to achieve it.

It is essential that it's an eclipse, or is it only essential that the planet is in some sort of darkness for the duration?

One highly plausible configuration (albeit that has been done before) is to have your planet orbiting a binary where one star is dark. The warmth-bringing star is at times near and far away, producing a long day-night like cycle. There are various ways of doing this, depending on what effects you're looking for.


But are you accounting for how cold it will get? I just read Stephen Baxter's Galaxias, in which the Sun winks out for a very short time, and the scientists go into detail about just how fast the planet will freeze and the global ecosystem will collapse, followed by various gases condensing out of the atmo. By the author's research it happens in way less than a year.

 

[Ibix]

Yeah, I don't think this is possible either. You can't really keep three stellar objects in a straight line for very long. You can have long eclipses (hours, maybe) on things like moons of gas giants, but not years.

Artificial worlds provide more opportunities, although your society is limited to a tech level that can't fix the issue.

 

[DaveC426913]

Yeah, I don't think this is possible either. You can't really keep three stellar objects in a straight line for very long. You can have long eclipses (hours, maybe) on things like moons of gas giants, but not years.

Artificial worlds provide more opportunities, although your society is limited to a tech level that can't fix the issue.

I was toying with a moon at L1, but realistically, not one large enough to do the job - and not naturally - and it would not return there.

I wonder though, what if the subject planet was at the L2 of a giant? Maybe an outer planet could disturb it from its stable position just enough to clear the giant's shadow for while.

Moght be within handwaving tolerance of the author.

 

[yh5598]

In my opinion, that premise is simply too big to handwave without justification.

My suggestion would be to base your story on a plausible scenario and be flexible in how your world is set up to achieve it.

It is essential that it's an eclipse, or is it only essential that the planet is in some sort of darkness for the duration?

One highly plausible configuration (albeit that has been done before) is to have your planet orbiting a binary where one star is dark. There are various ways of doing this, depending on what effects you're looking for.


But are you accounting for how cold it will get? I just read Stephen Baxter's Galaxias, in which the Sun winks out for a very short time, and the scientists go into detail about just how fast the planet will freeze and the global ecosystem will collapse, followed by various gases condensing out of the atmo. By the author's research it happens in way less than a year.

Thanks for the suggestion! It's not about the eclipse at all, that was what I first pictured when conceiving the story. I will look into the binary system, it just reminds me of binary sunset scene from star wars a lot and I was avoiding doing that configuration.

I will definitely check out the book. Yes, I wanted to explore a harsh condition where these swarm queen would take advantage of the freeze to lay eggs, and the human tribes figured out the pattern long ago and would retreat underground and re-emerge to battle the swarm. More researches to go about making the biology more realistic. This forum was my first stop and thanks for replying!

 

[Baluncore]

I was toying with a moon at the Lagrange point, but realistically, not one large enough to do the job - and not naturally.

L1 and L2 are in line, but they are not stable, so could not be arrived at, or maintained, without engineering.

 

[snorkack]

One example of a binary system is α Centauri. The 80 years orbital period straight inside your range of 70-100 years.
At some point I figured out: if a planet of one of them orbits near the orbital plane of α Centauri AB, within a few degrees of it (likely, all solar system planets orbit inside 7 degrees of invariable plane and half of us inside 1,1 degrees) and the planet then rotates at a moderate axial tilt (also likely, half of us are between 23 and 29 degrees), then while the local sun, in a polar area, rises and sets over the period of local year in polar nights and days... but the other star rises and sets over its orbital period of 80 years.
α Centauri AB´s orbit is also eccentric. Depending on the specific orientation of the axis of planet relative to the apside line of AB orbit, it would be possible for a pole of α Centauri planet to see the other star uninterruptedly as circumpolar star for 65 (Earth) years near apoapse and then not see it for 15 years near periapse. In which case the other pole sees the other star just for 15 years. Or depending on the axis orientation, both poles might see the other star for 40 years, one pole while approaching and the other pole while receding.
Since α Centauri A is brighter than Sun, an Earth-like planet orbiting α Centauri A would have to be further from α Centauri A than Earth from Sun and have longer year. By an obvious estimate, about 16 months.
So a centaur living on a pole could very well enjoy a period of 65 Earth years with winters (about 50 of them) but no night of any kind because α Centauri B never sets and always gives bright light. And then a period of about 15 Earth years when the winters (8 month long, 11 of them) are deep polar nights besides being cold). How would the centaurs adapt to not needing to deal with darkness 65 years at a time?

As for cold itself, that varies. Even now in Holocene, a polar night in Norway coast is as dark (darker when cloudy) but very much warmer than same latitudes in Siberia, Nunavut or Antarctica. Back in Eocene and Cretaceous, the whole Arctic and Antarctic must have been as dark in polar night as now, but were wooded, and with lush forests - apparently no snow cover at polar night! So you can decide how much meridional heat transport you are providing, within a vast range.

 

[Cerenkov]

Are you aware of this story, YH5598?

https://en.wikipedia.org/wiki/Nightfall_(Asimov_novelette_and_novel)

Living in the perpetual light of the six suns in their system the humanoid inhabitants of Lagash have never experienced true darkness. So if they were exposed, even for a short time, to the darkness of the night sky their minds would be unable to deal with this phenomenon.

I won't say any more about the plotline.

But you might find it interesting to compare this tale with your proposed scenario.

Thanks,

Cerenkov.