Tariniel

Any Astrophysicists or Biologists out there?

26 posts in this topic

So... I am writing a fantasy novel and have run into a bit of a snag. I have this thing (definitely an outgrowth of reading too much Sanderson) to have as much of my worldbuilding as possible have a concrete backing in scientific fact. The problem is that I know nothing about astrophysics, biology, or anything that could really help me work out the permutations of certain changes to the world.

Here's my current situation: The world I'm building is plagued by abnormally high temperatures throughout half the year (comparable to a constant heat wave) and similarly cold temperatures for the other half. They are mitigated by a short, two-week period of regular weather in between. During the Heatsurge there is week or so long period where the sun does not set, mirrored by a similar period during the Coldsurge when it does not rise. These events repeat in a constant, yearly cycle. The flora and fauna have all had to grow around these extreme conditions, with adaptability becoming even more important to survival.

My questions are twofold: First, is there a way to make this astronomically grounded. Would something like the axial tilt have to change to keep the continuing cycle of Hot and Cold surges, or does that have nothing to do with it? Multiple astral bodies? I don't know, just throwing things out there...

Second, how would the flora and fauna adapt to such extreme changes in temperature? I've been reading up on some animals' ability to survive temperatures below freezing using something called supercooling, but I feel I would need more of an adaptability factor here. This world's plants and animals have to be able to change throughout the year, as protection against one half of the year would likely be harmful during the other. Any biologically-adept people that can help me out here?

The original idea for this came out of a desire of mine to create something fundamentally connected to the world that affected all the life within it, from biology to culture to business (similar to the highstorms of Roshar). Let's see if this can work!

Hope you all can help me out! Thanks for your time!

Edited by Tariniel
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Disclaimer: I am not either one of the specialties you asked for. i am one of those people who have A LOT of random stuff floating in his head so take my answers with a grain of salt. 

Question 1:

Summery of my your seasons and solar events

               Summer Solstice "Longest day of the year": 1ish week of no sunset

               Fall/Sprint Equinox "Day and Night 12ish hours apeice": 2 ish weeks of fairly even days earthish environment

               Winter Solstice "Longest night of the year": 1 ish week of no sunset.

not really plausible even with a fairly deep tilt to the planet. unless your planet also slowed its rotation twice a year (at the solstices) which could be in world reasons for the Heat and Cold surges as well though this would likely need a second astral body to affect this kind of speed change.

Things to think about:

             Earth does this above the Arctic Circle there is nearly 6-months of sun then 6-months of no sun in fact that is what defined that line.

             North and south poles will be opposites

             Your corresponding Arctic and Antarctic Circles will be closer to the equator the deeper the tilt of your planet.

 

Question #2:

There are fish and plants in the Antarctic Seas that have a natural form of antifreeze so they can survive the freezing oceans. Penguins gather together to maintain body heat. so cold survival is possible watch blue planet and planet earth to get some ideas.

the same goes for your hot phases watch nature documentaries about deserts for some ideas on how it works here at home.

the trick is to have animals that have BOTH adaptations  and either can turn one set off or is something like the antifreeze in the blood, and waxy skin that prevents water loss that may be able to work with both extremes. 

 

I hope these ideas help and good luck.

 

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1 hour ago, Tariniel said:

Here's my current situation: The world I'm building is plagued by abnormally high temperatures throughout half the year (comparable to a constant heat wave) and similarly cold temperatures for the other half. They are mitigated by a short, two-week period of regular weather in between. During the Heatsurge there is week or so long period where the sun does not set, mirrored by a similar period during the Coldsurge when it does not rise. These events repeat in a constant, yearly cycle. The flora and fauna have all had to grow around these extreme conditions, with adaptability becoming even more important to survival.

High temperatures and sun not setting for half the year, low temperatures and sun not rising for half the year... That sounds like what happens to the seasons at the North/South pole, minus it actually being warm of course.

Although, if you were at a lower latitude so that the 6 months of daylight got reduced to only a week, there is a possibility that it would be able to heat up.. The concept seems moderately sound in reality, but lacks the temperature extremes you want.

Hang a plant upside down and it will still find a way to curve upwards towards sunlight. So life will definitely find a way, but it (animal life in particular) might be.. strange to say the least.

Never managed to click send huh..

@Tsidqiyah is right about having to fiddle with moons and things to get the 1,2,1 pattern that you're after, but for the life of me I haven't a clue how.

42 minutes ago, Tsidqiyah said:

Disclaimer: I am not either one of the specialties you asked for. i am one of those people who have A LOT of random stuff floating in his head so take my answers with a grain of salt. 

Edit: I should've put a similar thing at the start of my post. I'm no expert beyond 9th grade biology and 12th grade environmental science

Edited by The One Who Connects
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You guys both did two things: You provided me with some things to think about and possibly expand on, as well as succeed in making me not feel so bad about my ignorance. I'm currently a senior, so I haven't even finished that environmental science you speak of @The One Who Connects.

Regardless, I do have to find an expert on this sort of thing. Do either of you know someone, or somewhere, where I can get this information? 

Now on to your comments:

1 hour ago, Tsidqiyah said:

not really plausible even with a fairly deep tilt to the planet. unless your planet also slowed its rotation twice a year (at the solstices) which could be in world reasons for the Heat and Cold surges as well though this would likely need a second astral body to affect this kind of speed change.

Could you explain this a little more @Tsidqiyah? I assumed these changes would have something to do with astral bodies, and the world's axial tilt, but I'm not quite sure what you're saying here... Also, do you guys know if it would focus more on solar changes or lunar ones?

1 hour ago, The One Who Connects said:

Although, if you were at a lower latitude so that the 6 months of daylight got reduced to only a week, there is a possibility that it would be able to heat up.. The concept seems moderately sound in reality, but lacks the temperature extremes you want.

What do you mean by lowering the latitude? Do you know how exactly that would affect things?

1 hour ago, Tsidqiyah said:

the trick is to have animals that have BOTH adaptations  and either can turn one set off or is something like the antifreeze in the blood, and waxy skin that prevents water loss that may be able to work with both extremes. 

This is a great observation. I just need to figure out how to not make certain things contradict biologically, which will be no easy feat. One step at a time :)

Homework for me: I'm going to look into that antifreeze aspect of fauna in the Poles, as well as look farther into life and climate in those areas.

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2 hours ago, Tariniel said:

I'm currently a senior, so I haven't even finished that environmental science you speak of

We just needed a 4th science credit to graduate, so the last class was a take your pick. Meaning you might not even see it in HS.

2 hours ago, Tariniel said:

What do you mean by lowering the latitude? Do you know how exactly that would affect things?

You want to do things that are recorded in extremes at the poles (highest latitude). I simply meant that if your "city" or whatever was located a bit further south (High Canada/Siberia..ish) that you might get the same effect, but less extreme than 6 months of sunlight. No pulling a Lord Ruler and moving the Poles, just settling the city further down.

Edit: My English teacher would have words with me after reading that... :) North Pole = 6 Mo of Day/Night. It stands to reason that going further away might have a 3 Mo period with Day/Night. Although, considering that this phenomenon is fairly confined to the Poles, there would be a very narrow region with this effect unless you resort to a little handwavium

Edited by The One Who Connects
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3 hours ago, Tariniel said:

Could you explain this a little more @Tsidqiyah? I assumed these changes would have something to do with astral bodies, and the world's axial tilt, but I'm not quite sure what you're saying here... Also, do you guys know if it would focus more on solar changes or lunar ones?

OK starting with basic time definitions.

Chrono-Day = The time it takes for a planet to make a single complete rotation on its axis.

Solar-Day = Sun up to Sun down

Chrono-Year = the Time it takes for a planet to make a single revolution around its star

Lunar-Month = Full moon to full moon

Nearly every other time division is earth centric meaning I will try not to include them in my discussion below.

 

If a planet’s axis is perpendicular to its path of travel around its star only the poles will experience non setting suns (though the sun will always just a half sun so maybe it is an always setting sun?)

For every degree tilt a larger and larger portion of the planet will experience a non-setting sun for HALF the year. The line where the sun finally “Sets” is the Arctic/Antarctic Circle.  This continues until the axis of rotation is parallel with the path of revolution. When an entire half of the planet would experience half year Solar-days and half years Solar-Nights.

The depth of the tilt will only define how much of the planet sees a 1/2 year solar day, it won’t help with an entire week or sunlight.  Anything less than 1/2 year solar days but more than a Chrono-Day won’t occur without a second star or some sort of yo-yo like speed up slow down cycle

Did I confuse you more? If so I am sorry.

***Again science documentaries such as Nova will help with the conceptualization here. And Life or Planet Earth are great ones to discuss the solar patterns above the Arctic Circle.***

Spoiler

NOTE: A situation such as Taldain (The sun is always in the same spot in the sky at any given point.) is possible IF the Chrono-Day is exactly equal to the Chrono-Year AND the axis of rotation is perpendicular

 

NEW THOUGHT!: I think I know what would work for you. A DEEP almost comet like ellipse for the planetary orbit. Such that it will take the planet the weekish time frame at the solstices to round. Now to achieve the week of constant sunlight put in a second sun. The trick is to have something at the other end that will black out the suns’ light in the winter, this could be moon like body, or something atmospheric such as the clouds getting heavier due to the cold.

This comet like orbit would also even explain the environmental shifts as well.

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5 hours ago, Tariniel said:

Here's my current situation: The world I'm building is plagued by abnormally high temperatures throughout half the year (comparable to a constant heat wave) and similarly cold temperatures for the other half. They are mitigated by a short, two-week period of regular weather in between. During the Heatsurge there is week or so long period where the sun does not set, mirrored by a similar period during the Coldsurge when it does not rise. These events repeat in a constant, yearly cycle. The flora and fauna have all had to grow around these extreme conditions, with adaptability becoming even more important to survival.

This is very similar to the conditions in some parts of Russia. Just north of the Arctic Circle, you get a few days of constant sunlight around the summer solstice and a few days of no sunrise around the winter solstice. (As you move toward the North Pole, it increases - at Barrow, Alaska it's about 2 months of each, and at the North Pole it's 6 months of each with no "normal" day/night cycle at all.)

Eurasia is such a large continent that its interior has very extreme temperature variations - almost no moderation by the ocean. Some parts of Siberia even get rather hot in the summer (at least sometimes), despite being utterly cold in the winter.

So, you don't really need to do anything weird with the orbit to get the conditions you mention. Consider a planet that's much drier than Earth (say ~20% ocean instead of ~70%), with the seas primarily around the equator. Make the tilt a bit more extreme, to push the Arctic Circle south into warmer latitudes (and thus make the summer hotter).

There will be a narrow band of mostly nice areas around the seacoasts, but this can be broken up by deserts (on Earth major hot deserts tend to fall just outside the tropics - the Sahara and the SW US/NW Mexico deserts in the northern hemisphere and  the Namib, Atacama, and the Australian Outback in the southern).

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1 hour ago, Tsidqiyah said:

OK starting with basic time definitions.

 

Chrono-Day = The time it takes for a planet to make a single complete rotation on its axis.

The normal term for this is "sidereal day", measured in relation to "the fixed stars" (IE - a reference frame outside the solar system).

1 hour ago, Tsidqiyah said:

The depth of the tilt will only define how much of the planet sees a 1/2 year solar day, it won’t help with an entire week or sunlight.  Anything less than 1/2 year solar days but more than a Chrono-Day won’t occur without a second star or some sort of yo-yo like speed up slow down cycle

Actually, no, you only get the half-year day/half-year night at the Poles themselves. At the Arctic Circle you get one day of zero sun and one day of total sun. In between, you get something in between. At Barrow, Alaska (71 degrees north) there is a bit over 2 months of no sunrise and 2 months of no sunset.

(Much of the 'sunless' polar night still has significant twilight however.)

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2 hours ago, cometaryorbit said:

This is very similar to the conditions in some parts of Russia. Just north of the Arctic Circle, you get a few days of constant sunlight around the summer solstice and a few days of no sunrise around the winter solstice. (As you move toward the North Pole, it increases - at Barrow, Alaska it's about 2 months of each, and at the North Pole it's 6 months of each with no "normal" day/night cycle at all.)

Yay, I assumed right! Upvote for you.

2 hours ago, Tsidqiyah said:

The trick is to have something at the other end that will black out the suns’ light in the winter, this could be moon like body, or something atmospheric such as the clouds getting heavier due to the cold.

Random Facts about Cloud Cover: (source is.. interesting, feel free to fact check me)

  1. Water vapor in cool air is what creates clouds. (If you have some humidity, then the clouds could easily get thicker with the cold season)
  2. Air pollutants that reflect sunlight increase cloud cover. Pollutants that absorb sunlight stunt cloud formation (More for OP, but it's here for the purpose of discussion)
  3. Cloud Cover on Venus traps heat in the atmosphere, so super greenhouse effect occurs (Bit of danger if OP goes with the pollution idea)
  4. Daytime: more clouds = cooler temperature. Nighttime: more clouds = warmer temperature. (Double edged sword that one)
  5. Sidenote for Plantlife: high heat & low humidity dries out soil and makes it unhealthy (adapt for low nutrient intake, like cacti and water?)

Heat from sunlight evaporates water vapor, which creates clouds. Correct me if I'm wrong, but that would make sunny season rather cloudy and night season fairly cloudless right?

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3 hours ago, The One Who Connects said:

Yay, I assumed right! Upvote for you.

Random Facts about Cloud Cover: (source is.. interesting, feel free to fact check me)

  1. Water vapor in cool air is what creates clouds. (If you have some humidity, then the clouds could easily get thicker with the cold season)
  2. Air pollutants that reflect sunlight increase cloud cover. Pollutants that absorb sunlight stunt cloud formation (More for OP, but it's here for the purpose of discussion)
  3. Cloud Cover on Venus traps heat in the atmosphere, so super greenhouse effect occurs (Bit of danger if OP goes with the pollution idea)
  4. Daytime: more clouds = cooler temperature. Nighttime: more clouds = warmer temperature. (Double edged sword that one)
  5. Sidenote for Plantlife: high heat & low humidity dries out soil and makes it unhealthy (adapt for low nutrient intake, like cacti and water?)

Heat from sunlight evaporates water vapor, which creates clouds. Correct me if I'm wrong, but that would make sunny season rather cloudy and night season fairly cloudless right?

Cloud formation is complicated. Yeah basically it's water vapor cooling to condense into droplets (that's why cumulus type clouds tend to have those very flat bases - at the level of the atmosphere where it gets cold enough to condense).

But there are wrinkles that can affect it. It involves 'cloud condensation nuclei', tiny particles in the atmosphere. Even particles that absorb sunlight (are dark) can act as nuclei.

The pollutants reflecting sunlight has to do primarily with formation of nuclei (either direct release of particles like soot/smoke or reactions with pollutant particles. Sulfur dioxide reactions to produce sulfate particles is a major one - this is also the major factor in the 'year without a summer' effect from really big volcanoes. These very small particles stay up longer & make a larger difference than the actual ash, as I understand it.)

The clouds on Venus probably trap some heat, but the real factor there is its ridiculously CO2 filled atmosphere (it's about 90 atmospheres of CO2, vs. current Earth levels of 0.04% of one atmosphere - 225,000 times more!) Venus' clouds are so reflective that the planet actually absorbs less solar energy than Earth (the sunlight is twice as intense, but Venus is more than twice as reflective.)

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Has anyone given any thought yet about the tropics? On earth, they're called the tropic of cancer and tropic of capricorn. The point is that as your arctic circles move toward the equator the tropics move away from it, so that if your axial tilt is 45° they're the same thing. No idea how that affects the climate or even much of day length, I just wanted to remind people that it's not just about the arctic circles, there are other factors at play.

No idea if the following suggestion is viable, but what if the story is set on a moon? If the planet the moon orbits is extremely reflective, it might act as a second sun in some respects, without the whole binary star-system problematic. And the cold season is when the moon passes behind the night-side of the planet, with the two-week night period being when the planet blocks the sunlight (moon is on an orbit with a steep angle to the elliptic), the two week sun period is when the moon is directly between the planet and the sun, so the direct daylight and the planet-reflected daylight cover (nearly) the entire surface.

Can't help with the biology, but everyone's suggestion of watching documentaries is probably a good one.

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What inhabits your world? Cos they must be made of stern stuff.

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One piece of advice to take from Brandon is to realize the benefits of writing a fantasy in that you can have fantastical solutions to problems, eg. spren that help Roshars greatshells not be crushed under their own weight, magic microbes that eat volcanic soot from the ashmounts on Scadrial, etc.

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You could have everything just transform between seasons. Everything has a 'Summer' and a 'Winter' form that they switch between.

I think that could be very interesting, having a planet where everything is completely different depending on the time of the year. So wolves turn large and fluffy during summer and smaller and ... less fluffy during summer, for example, unless you really want to go the sci-fi route.

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6 hours ago, Voidus said:

One piece of advice to take from Brandon is to realize the benefits of writing a fantasy in that you can have fantastical solutions to problems, eg. spren that help Roshars greatshells not be crushed under their own weight, magic microbes that eat volcanic soot from the ashmounts on Scadrial, etc.

Yes, but even behind those hand-waviums (misdirections) Brandon usually has a scientific explanation. He uses magic to explain the last couple of impossibilities, but he gets as far as he can through scientific means. This blend of scientific background with a fantasy-type storyline is something I actually got from him, as it is one of the things I find most fascinating about his books. Take the greatshells, for example:

Quote

"Roshar is smaller than Earth and, as a result, its surface gravity is, at 0.7g, significantly weaker than Earth's. This is part of what allows some of the native creatures to grow so large." -- Coppermind

"Due to power laws, larger creatures cannot use the same shape as smaller creatures – Kaladin makes the comment a few chapters ago that the chasmfiend is “wrong” in it’s proportions for a creature of it’s size. Putting it another way, an elephant has to be slow and bulky due to its size. The weight that bones can carry is proportional to their area – so if you double the radius of a bone the weight it can carry increases by 4x. But if you double each length of a creature its weight increases by 8x. So the bigger a creature becomes the (proportionally) thicker the bones need to become." -- Comment by ChrisRijk on Tor's WoR Chapter 72 Reread

"I did a lot of reading about weights of various woods, did a lot playing with the length, the span between the chasms, etc. One thing that people should know if they are trying to figure all this out is that Roshar has less gravity than Earth does. This is a natural outgrowth of my requirements both for the bridges and for the size of the creatures that appear in the book–of course they couldn’t get that large even with the point-seven gravity that Roshar has, but we also have magical reasons they can grow the size they do. That’s one factor to take into account." -- Brandon Sanderson

 

6 hours ago, Zathoth said:

You could have everything just transform between seasons. Everything has a 'Summer' and a 'Winter' form that they switch between.

This is really what I am shooting for. I find it fascinating the way that, not only animals, but cultures would build around having to live completely differently throughout the year. My issue with the animals was that I am not sufficiently adept at biology to find an anatomically probable way they would use to switch off. This discussion has given me a couple of ideas, which I am currently fleshing out into something somewhat coherent :) 

Thanks for your awesome answers everyone, and thanks @cometaryorbit for bringing your obvious expertise to this thread. I have a couple of question, but they'll have to wait until the morning. Taking the ACT tomorrow, need to get my sleep in :unsure:

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@cometaryorbit thanks for the correction overall thusis helping me with my world  for my Nanowrimo  entry.

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On 10/21/2016 at 11:54 AM, Tariniel said:

Second, how would the flora and fauna adapt to such extreme changes in temperature? I've been reading up on some animals' ability to survive temperatures below freezing using something called supercooling, but I feel I would need more of an adaptability factor here. This world's plants and animals have to be able to change throughout the year, as protection against one half of the year would likely be harmful during the other. Any biologically-adept people that can help me out here?

How extreme are the temperature swings? Are we talking 100 F summer noon / -70 F winter night or something worse? In the first case, Earth-type adaptations ought to work fine.

Coniferous trees can survive bitterly low temperatures in the Siberian taiga winter. Their narrow needles limit water loss (water is not available to them when the ground is frozen) & are protected by a waxy covering. At least some have the ability to survive freezing by pushing the water that would freeze outside their cells, so the ice doesn't tear up cell membranes ("extracellular freezing"). They are largely dormant, too.

Most creatures will probably be dormant during deep winter, or migrate. (The Arctic Tern migrates from the Antarctic to the Arctic, so it gets both polar summers and neither polar winter. Of course, that only works if the hot/cold seasons are caused by the tilt of the axis, and thus opposite in opposite hemispheres. A planet whose seasons were caused by a very elliptical orbit would have them simultaneously in both hemispheres.)

Some animals can do a version of the extracellular freezing trick, too. The wood frog and some insects can freeze solid and survive. IIRC, there's an insect larva that can go into basically suspended animation by drying out ("cryptobiosis" / "anhydrobiosis") and in this state it can survive being dipped in liquid nitrogen.

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10 hours ago, Tariniel said:

This is really what I am shooting for. I find it fascinating the way that, not only animals, but cultures would build around having to live completely differently throughout the year. My issue with the animals was that I am not sufficiently adept at biology to find an anatomically probable way they would use to switch off. This discussion has given me a couple of ideas, which I am currently fleshing out into something somewhat coherent :) 

You don't need a biological way if you have magic, as long as the magic is reasonably hard.

But like I said, if the sci-fi way is the way you want to go that is cool.

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13 hours ago, cometaryorbit said:

How extreme are the temperature swings? Are we talking 100 F summer noon / -70 F winter night or something worse? In the first case, Earth-type adaptations ought to work fine.

I'm not really sure about this, either. How extreme do you think they would have to be, to cause a significant evolutionary change in the flora and fauna?

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On October 21, 2016 at 6:41 PM, Tsidqiyah said:

NEW THOUGHT!: I think I know what would work for you. A DEEP almost comet like ellipse for the planetary orbit. Such that it will take the planet the weekish time frame at the solstices to round. Now to achieve the week of constant sunlight put in a second sun. The trick is to have something at the other end that will black out the suns’ light in the winter, this could be moon like body, or something atmospheric such as the clouds getting heavier due to the cold.

This comet like orbit would also even explain the environmental shifts as well.

Okay, this has sparked something in me. Do you think you could explain a little more of the 'why's in addition to the 'what's?

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On the biology side:

On 10/23/2016 at 3:49 PM, Tariniel said:

How extreme do you think they would have to be, to cause a significant evolutionary change in the flora and fauna?

The suggested range of sustained temperatures (-70F to +100F) would be more than adequate to drive adaptation.

@cometaryorbit gave some great examples of cold adaptations we see on earth, including migration, dormancy, and cryptobiosis. Remember that you will have lots of different strategies exhibited by different species. Additional examples to consider: the Mongolian gazelle changes its coat thickness and color, and its activity cycle. During the summer it is active primarily at dawn/dusk, while in winter it is active during the middle of the day. Various species of cicada have a timed life cycle such that their eggs lie dormant for some number of years (11, 13, or 17), then all hatch at once, swarm, and lay eggs within two months. This is a strategy to avoid predation, but aspects of it could apply to weather.

Extreme heat adaptations include estivation (hibernating when it gets too hot), high surface area structures for heat release (like long rabbit ears), reflective coatings, umbrella-like parts that make shade.

Also note that warm blooded and cold blooded strategies to both heat and cold will be substantially different. An imaginative approach could design an animal that shifts from internal to external temperature regulation. That would create some severe weirdness at the molecular level, but my initial reaction against the idea is fading as I think about potential mechanisms.

Two ideas for integrating hot and cold adaptations, just to get you thinking. You have a deer with antlers. During the hot season the antlers grow highly vascularized skin so that the blood flow can shed heat. Turn off the blood flow when it gets cold, and you loose that surface for heat loss. Give that deer huge fat pads on their feet to insulate them from the hot ground. As the temperature shifts, metabolize that energy and redistribute it as a blubber coat beneath the skin, leaving a much smaller contact patch with the frozen ground.

One other possibility to remember is symbiotic relationships. Maybe you have a cold-adapted bird and a heat-adapted reptile that go mostly dormant in the off-season, but each protects/carries/feeds the other in turn.

An example to look at from fiction: the aliens in Vernor Vinge's A Deepness in the Sky live on a world with a much more protracted cycle, with years of cold or warmth. Their strategy is basically cryptobiosis. They freeze themselves in holes deep in the ice for the 200-year winter, popping out to resume their activities when everything thaws. I don't remember how much he developed the rest of the ecology, but might be worth looking at.

Oh, and the ever-popular tardigrade is adapted to survive just about anything. Many of those things work because they are tiny, but with a combination of science and magic you might come up with believable ways to make them scale up for other organisms.

On the astrophysics:

There are a few things to decide about how you want your world to work. The first is how much of the world undergoes this cycle, and whether it does so in sync. As others have pointed out, It wouldn't take too much tweaking to get conditions close to what you suggest slightly above the arctic circle. If you have a long, thin continent, or an archipelago, or an isolated region of a continent, you could get this effect in a localized way. Importantly, the cycle in the other hemisphere would be out of sync. This would bias your system toward migrational and shelter-in-place type adaptations. If you do something else with the world to make the fluctuations simultaneous, or if you make migration unfeasible (a la Scadrial's uninhabitable equatorial region) you will bias it towards metamorphoses and behavioral changes.

Remember that more than just orbit characteristics impact meteorology. Local geography (mountains, bodies of water, trade winds, currents) etc. have a huge impact. If the effect is relatively localized rather than planet-wide, you can leverage those sorts of things into your explanation. If you want, you could also add geothermal activity to create some cave systems with survivable temperatures for those creatures (like people) who don't dessicate themselves.

Verkhoyansk in Siberia holds the record of widest temperature range on Earth. It does that mostly by being one of the coldest places during the winter, but it also gets up to >90F some of the time. A big part of what allows Siberia and other places to have those sorts of ranges is that they are far from large bodies of water, which generally act as heat sinks and prevent huge swings in temperature. You may want to research the sorts of adaptations that take place in those locations.

If you do try for an elliptical orbit of some sort, remember that such a planet will spend more time in the distant portion of the orbit than in the close-to-the-star part, so you won't get equal halves of the year very easily that way.

Another idea to throw into your considerations is something to block the sunlight. Maybe there is a dense asteroid belt or dust cloud between the planet and its star, but the planet's orbit is inclined just enough to bob in and out of the shadow. This would give you two hot-cold cycles per solar year, but I doubt that would be a problem for the setup you are creating.

(The other conclusion of what I'm seeing in this thread is that your temperature difference doesn't necessarily have to be caused by the same thing as your periodic weeks of dark and light. They will probably impact each other, but could have entirely separate origins and cycles, depending on the world building you choose to do.)

 

Edited by ccstat
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14 hours ago, ccstat said:

An imaginative approach could design an animal that shifts from internal to external temperature regulation. That would create some severe weirdness at the molecular level, but my initial reaction against the idea is fading as I think about potential mechanisms.

That's a very interesting concept. There are some "in-between" systems on Earth, like the great white shark (non-constant body temperature, but kept significantly warmer than the environment by internal heat production - IIRC it's constantly X degrees above the water around it rather than stabilized at a constant temperature like a mammal.)

A creature might be able to shift between a low-metabolic rate, low-food requirements state where its temperature was similar to the environment's, and a high-metabolic rate, high-food requirements state where its temperature was significantly above the environment's.

15 hours ago, ccstat said:

An example to look at from fiction: the aliens in Vernor Vinge's A Deepness in the Sky live on a world with a much more protracted cycle, with years of cold or warmth. Their strategy is basically cryptobiosis. They freeze themselves in holes deep in the ice for the 200-year winter, popping out to resume their activities when everything thaws. I don't remember how much he developed the rest of the ecology, but might be worth looking at.

 

There's a setup in Hal Clement's Cycle of Fire where a planet in a binary system switches between long periods (50-60 years or so) of Earthlike temperatures and super-hot temperatures. The composition of the atmosphere changes radically, and there are basically two totally different ecologies, and two intelligent species, dominant in the different phases. (During the 'wrong' season, they're dead except for spores of some sort symbiotic with the opposite kind of life.) There are small refuges (in the polar ice caps for the 'cool' species and in volcanic areas for the 'warm' species) where a few survive the 'wrong' season and pass on knowledge to the new generation.

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If you do try for an elliptical orbit of some sort, remember that such a planet will spend more time in the distant portion of the orbit than in the close-to-the-star part, so you won't get equal halves of the year very easily that way.

 

Yes... and to get the extreme changes you're talking about, planet-wide, it would have to be very elliptical. Also, because of seasonal lag (takes time for atmosphere and especially oceans to heat up, which is why the hottest time of year a lot of places is late July/early August when the maximum sunlight is around June 21), the hottest time will be after that brief closest-to-sun period.

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8 hours ago, cometaryorbit said:

There are some "in-between" systems on Earth, like the great white shark (non-constant body temperature, but kept significantly warmer than the environment by internal heat production

Very cool. How did I not know about this? Here are the relevant wikipedia links for the rest of you curious folks.

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What if the planet had a different rotation? If the sun rose in the north and set in the south, for example. During two quarters of the year, things would be normal, however during the other two quarters, whichever side the sun is on would determine where the cold/hot seasons were. It might also be interesting for a planet to have a different rotation than earths for a change. Opinions?

Edited by ShadowLord_Lith
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7 hours ago, ShadowLord_Lith said:

If the sun rose in the north and set in the south, for example. During two quarters of the year, things would be normal, however during the other two quarters, whichever side the sun is on would determine where the cold/hot seasons were.

So, as I mentioned, I'm not the most adept mind when it comes to this sort of thing. It seems to me, however, that this would only affect the time of the seasons, and not their length or power (which is really what I'm shooting for.) It seems like something cool to add simply for the variety, but would it really change much?

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