Orbital patterns

[j9mes]

Hi everyone. This is my first post and I am a novice, but have an interest in planets and orbital patterns.

Is it possible for a planet to orbit a sun and be in partial or complete darkness for long periods of time - for example a year or more? If it is possible, would it only be because of of the planet spinning on its axis, or could it be because the elliptical orbit is uneven and takes it farther away during one phase then closer during another? Would the planet be able to recover from the lack of photosynthesis and freezing conditions of being in darkness for a year? How would this affect life on the planet?

I welcome any comments or explanations in relation to this topic.

Many thanks

Edited April 1, 2016 by j9mes

[Strange]

One side could be in darkness al the time but I am not sure how the whole planet could be.

 

Brian Aldiss wrote a trilogy (Helliconia) about a planet with very long seasons - thousands of years - which might be something like you are thinking of. I don't remember how he contrived this. It might have been an extremely elliptical orbit.

[swansont]

Venus only rotates once every 243 (earth) days but takes 225 to complete an orbit. That would have half the planet in darkness for a long time.

[j9mes]

@ Strange - Thanks. I'd never heard of the Helliconia Trilogy before and will definitely give it a go. After looking at the Wikipedia page it seems exactly the sort of thing I'm interested in exploring.

 

@swansont - Thanks. This sound interesting. I'll do some more research on Venus I think ...

[Strange]

You might want to look into "tidal locking" as well. It is what keeps the moon's orbit and rotation synchronized so we only ever see one side of it.

[Delta1212]

What about a moon orbiting a gas giant? You might be able to tweak the orbit, size of the planet and distance from the sun to get a fairly extended period of eclipse that actually would put the entire world into darkness, although precisely how extended I'm not sure, especially if you want the moon to be habitable without life support systems of some kind (since it would need to be a fair distance out from its star, I think. Not because the darkness would necessarily render it uninhabitable itself).

[Janus]

What about a moon orbiting a gas giant? You might be able to tweak the orbit, size of the planet and distance from the sun to get a fairly extended period of eclipse that actually would put the entire world into darkness, although precisely how extended I'm not sure, especially if you want the moon to be habitable without life support systems of some kind (since it would need to be a fair distance out from its star, I think. Not because the darkness would necessarily render it uninhabitable itself).

To get a longer eclipse, you need a higher, slower orbit around the gas giant. The higher the orbit, the smaller the angular size of the gas giant as seen from the planet and the smaller the fraction of the orbit that it will eclipse the star. Since there is also a limit on how far the plant can orbit from the gas giant (hill sphere), I just don't see a way of making the eclipse period last even as long as 1 day.

[Enthalpy]

A moon at Lagrange's L2 point, but my intuition is that the shadow is not quite dark. Better have a planet without an atmosphere. In addition, the moon would move around L2.

 

Life:

Mushrooms living in the soil or an ocean would need no sunlight and benefit a constant temperature. These could throw aerial parts when conditions are decent.

Some terrestrial spores are known to hibernate for long in the cold and bring organisms to life under better conditions.

[Janus]

A moon at Lagrange's L2 point, but my intuition is that the shadow is not quite dark. Better have a planet without an atmosphere. In addition, the moon would move around L2.

 

Life:

Mushrooms living in the soil or an ocean would need no sunlight and benefit a constant temperature. These could throw aerial parts when conditions are decent.

Some terrestrial spores are known to hibernate for long in the cold and bring organisms to life under better conditions.

With a Jupiter sized gas giant at 1 AU, a body at L2 would be completely within the umbra. However L2 is not stable and a body placed there will drift away if even slightly perturbed. I just don't see a moon staying there long enough to develop an ecology.