The year of this planet is 1,000 earth-days-long around its star, and its night lasts half a year.

Can it support life such as Earth?

With humans and lush forests and liquid water and good temperatures and deserts and animals.

Note: star and planet and moons can be modified.

Edit: this planet is bigger than earth, the size is not specific and can be modified to meet the requirements, same goes for mass and everything else.

  • $\begingroup$ What do you mean by "500 continuous nights and then 500 continuous days"? $\endgroup$
    – Mike Scott
    Jun 10 '17 at 19:55
  • $\begingroup$ it's unclear what do you mean with 500 continuous night, you don't say anything about the planet structure (mass, size, composition). there is no way we can try to answer. $\endgroup$
    – L.Dutch
    Jun 10 '17 at 20:00
  • $\begingroup$ @MikeScott i mean that there will be 500 nights in a row and after than 500 days in a row. $\endgroup$
    – Maxwell
    Jun 10 '17 at 20:07
  • $\begingroup$ @Maxwell So what comes in between one night and the next one? $\endgroup$
    – Mike Scott
    Jun 10 '17 at 20:07
  • $\begingroup$ @L.Dutch i edited the post to answer your question, the fact is i have no values for the composition and mass and size and they can be whatever is needed to meet the closest match. $\endgroup$
    – Maxwell
    Jun 10 '17 at 20:08

Since this planet takes so much longer than Earth does to go around its star, I'm assuming the star will be brighter than the Sun, since the planet will have to be farther away. So it won't be a star like our Sun: it will be either a larger, brighter main-sequence star or a star originally like our Sun that has turned into a red giant.

Having such long nights and days means that the planet is almost as good as tide-locked. The planet will need a dense atmosphere to act as a buffer, preventing temperature extremes. An atmosphere can shield the planet from the sun's heat during the day and keep the heat when the sun goes down.

Water is also a very efficient temperature moderator. Oceans and lakes can absorb heat slowly during the day and then radiate it again during the night. Water also evaporates forming clouds that reflect sunlight back to space.

I remember reading of a science fiction story in which most animals coped with a situation like this by migrating continuously, following the sun. The worst place to do this would be the equator, since that's where the planet rotates the fastest. If your planet is a bit larger than Earth (say, with an equatorial circumpherence of 50000 km) and it rotates once every 500 Earth days, then an animal that wanted to stay all the time under the sun would have to move at a rate of 100 km per day along the equator. Even that is not too much, actually (some large Earth animals often travel that distance in a day looking for food).

As for plants and slower animals, maybe they could do what many Earth organisms do: lie low and hibernate during the night, wake up and reproduce during the day.

As for humans, maybe we could develop a mixture of these strategies. We could be engineered to be able to "shut down" and hibernate, or develop a nomadic civilization.

  • $\begingroup$ thank you very much. why would the humans migrate or hibernate though? i mean if what you said works then it shouldn't be too cold or too hot to live isn't that correct? or are you talking specifically about equator? $\endgroup$
    – Maxwell
    Jun 10 '17 at 21:38
  • $\begingroup$ Would you live through a 500-day night? Merely not freezing is not enough, you have to have food, energy, etc. while everything else around is on hold. That's a riddle you'll have to solve. $\endgroup$
    – pablodf76
    Jun 10 '17 at 21:47
  • $\begingroup$ that's correct. but what if the plants and fruits and some animals had evolved to produce food, or they could stack the food too. then that would work out smoothly right? $\endgroup$
    – Maxwell
    Jun 10 '17 at 21:53
  • $\begingroup$ also, i would imagine the plants and animals that function through the night have developed special tools for themselves (like on earth with some plants and animals that glow or can see in dark and only operate during the night) correct? $\endgroup$
    – Maxwell
    Jun 10 '17 at 21:56
  • $\begingroup$ Venus has a thicker atmosphere, and yet I would not dare saying it is shielded by temperature extremes... $\endgroup$
    – L.Dutch
    Jun 11 '17 at 3:34

If your world does not have to orbit once every 1000 days you could have a day/night cycle equally long by making it rotate itself in a way that slows the rate at which it changes its facing sides and day/night cycle. This would while having a much shorter time period of orbit needed would keep the long day and night cycle you want.

A quote from the article URL below, "As long as the planet has an ocean and a dense enough atmosphere, they will likely circulate and carry heat around. So temperatures can be evened out on the day-night sides, despite the planet's lack of rotation." http://www.npr.org/sections/13.7/2014/05/06/310086953/habitable-planets-may-not-look-exactly-like-the-earth

This was for really small planets that have no change in day/night but it could still apply in your planet's case.

Honestly while temperature extremes will make things difficult it will not make things impossible to survive while staying put. While a huge east-west band of ocean and a thick atmosphere will help to even things out this still has bad implications during the night season. A difficulty in having active plant life for animals to feed on is going to drop the carrying capacity exponentially. One way to help circumvent this would be to have a much brighter (at least 100 times more Lux (light per meter) than the full moon) celestial body that is always fixed in the same position in the night sky. This could be done by a planet that is made of an extremely reflective surface around the size of Venus with a ring around it roughly 27 degrees or more (ones like Saturn's). This outer planet could move quicker in space letting it keep pace with the slow rotating planet you are talking about.

This would in theory allow shade tolerant cyanobacteria (photosynthetic bacteria) to receive enough PAR (plant version of Lux) to allow growth. Considering how cyanobacteria is so vital to our ocean ecosystems this would allow much higher food production than it would be otherwise. So while the lack of daylight would hurt things, it would hardly be crippling. Furthermore not all life requires light. Chemo-synthetic plants would help increase biomass in small pockets. Also a hypothetical heat type photosynthesis might not be impossible either. Do not misunderstand what I am saying as migration will still be the main way of life for most of the complex lifeforms on this planet.

If this planet was at a 0ish degree axis it would most likely just become a more dramatic seasonal changes with day=summer, sunrise/sunset for spring/fall and, night as a dark winter.


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