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Noclevername
2015-Jul-22, 10:59 PM
I'm worldbuilding a planet for a story, which contains a large (twice-Asia-sized) landmass sitting on the polar cap. I know about Arctic and Antarctic climate/biome regions, but how can I design what would fit in between them?

ADDED: Forgot to say, the planet has a 50-hour day, life-bearing with breatheable air, and is otherwise Earthlike.

Solfe
2015-Jul-22, 11:26 PM
Like Amasia (https://en.wikipedia.org/wiki/Amasia_(continent)). Also see articles at NPR (http://www.npr.org/2012/02/08/146572456/amasia-the-next-supercontinent) and SA (http://www.scientificamerican.com/article/next-supercontinent-amasia-wil/).

Perhaps there are vast frosty salt lakes or a large ring of mountains at the north pole.

Here is another link - http://www.sciencearchive.org.au/nova/newscientist/104ns_011.htm

starcanuck64
2015-Jul-23, 05:28 AM
From what I recall from reading a book on the Snowball Earth theory, when most of the land masses are located along the equator then runaway glaciation becomes a possibility, so maybe having most of the landmass oriented at one pole would create a more stable and possibly warmer climate.

grapes
2015-Jul-23, 08:37 AM
From what I recall from reading a book on the Snowball Earth theory, when most of the land masses are located along the equator then runaway glaciation becomes a possibility, so maybe having most of the landmass oriented at one pole would create a more stable and possibly warmer climate.
A snowball earth is pretty stable, though. :)

Landmass (particularly land with snow) reflects more heat than the open water. Putting the continents at the poles could place more energy in the water, which could result in extreme weather patterns.

BigDon
2015-Jul-23, 03:20 PM
What Grapes said.

You don't want too much land on the equator.

starcanuck64
2015-Jul-23, 07:03 PM
A snowball earth is pretty stable, though. :)

Landmass (particularly land with snow) reflects more heat than the open water. Putting the continents at the poles could place more energy in the water, which could result in extreme weather patterns.

And offers year round skiing at any location.

I think ice cover reflects about 90% of sunlight while open ocean absorbs about the same amount so there would be far more heat being stored in the global climate. I imagine you could also get some massive hurricanes forming with all the heat available from warm surface water.

John Mendenhall
2015-Jul-23, 08:13 PM
I'm with grapes and BigD. My first thought was bad weather, and they gave good reason why.

How about a dry no ice polar desert?

starcanuck64
2015-Jul-23, 08:23 PM
You also need to look at things like the age of the planet which will determine how much carbon dioxide there would be in the atmosphere which plays a major role in moderating the global climate. If the day is 50 hours long - and there's a large moon - there's a good chance this is a very old planet where tectonic activity has greatly diminished resulting in much less CO2 in the atmosphere which would be compensated to some degree by a warmer sun as it aged.

A lot of things to ponder in creating a convincing but very interesting fictional environment.

Noclevername
2015-Jul-23, 09:19 PM
You also need to look at things like the age of the planet which will determine how much carbon dioxide there would be in the atmosphere which plays a major role in moderating the global climate. If the day is 50 hours long - and there's a large moon - there's a good chance this is a very old planet where tectonic activity has greatly diminished resulting in much less CO2 in the atmosphere which would be compensated to some degree by a warmer sun as it aged.

The planet is roughly the same age as Earth. The star it orbits is slightly cooler but the planet is closer. 1.19 G surface. The land area is largely mountainous.

I'm thinking "large moon" isn't enough to account for the slow spin. A double planet, perhaps partly tide-locked? One livable, one not?

Jeff Root
2015-Jul-23, 10:19 PM
My own view is that the rotation speed of a planet is largely
random -- a result of many impacts of all different sizes.
It will start out rotating in the same direction as its orbit
around the star, due to gradual accretion of dust and gas,
but a few really big impacts later on can make the planet
rotate in any direction, at any speed.

-- Jeff, in Minneapolis

starcanuck64
2015-Jul-23, 11:15 PM
The planet is roughly the same age as Earth. The star it orbits is slightly cooler but the planet is closer. 1.19 G surface. The land area is largely mountainous.

I'm thinking "large moon" isn't enough to account for the slow spin. A double planet, perhaps partly tide-locked? One livable, one not?

I wonder what effect the slower rotation would have on weather and specifically storm formation. Hurricanes spin up close to either side of the equator and depend to a certain degree on the coriolis effect from what I recall.

You might also look at Antarctica in much earlier times when it supported a much more diverse ecology and was probably much more temperate in its interior with distinct seasons and more tropical around its coastline.

Here's a Scientific American article that also describes how oxygen content in the Earth's atmosphere may have played a role in climate. You can play around with a large number of factors to produce all sorts of interesting scenarios for unique worlds.

http://www.scientificamerican.com/article/oxygen-may-have-thawed-antarctica-in-dinosaur-times/

Darrell
2015-Jul-24, 03:53 PM
How slow? Too slow and your magnetic field won't be strong enough to effectively protect the surface of the planet from the local suns "wind".

BigDon
2015-Jul-24, 05:01 PM
A 50 hour day is also a cubic buttload of insolation.

Your days are going to be hellish by local "5PM".

Noclevername
2015-Jul-24, 05:15 PM
A 50 hour day is also a cubic buttload of insolation.

Your days are going to be hellish by local "5PM".

So to get a cooler day, I can move the planet outward from its sun. (The main action of the story already takes place on a Himalaya style high plateau.)

I was also tinkering with a minimal axial tilt and a more elliptical orbit, to give a longer winter. This would (I think) ramp up the oceanic weather during summer but lessen it during the rest of the year. So there'd be a "storm season" and a "calm season".

Noclevername
2015-Jul-24, 05:16 PM
How slow? Too slow and your magnetic field won't be strong enough to effectively protect the surface of the planet from the local suns "wind".

A slightly thicker atmosphere can take care of that. By lowering the oxygen content slightly I can make sure the partial pressure of O2 is the same as Earth at sea level.

BigDon
2015-Jul-24, 05:51 PM
Clev, just so you know, I'm not trying to beat up your idea. I love a good gaming/story world.

I was talking about the equatorial regions. Plus all that sunlight pumping gigatons of water vapor into the air. I'd say, oh, roughly twice as much as what occurs on Earth.

The poles could be home to all manner of advanced fungoids.

starcanuck64
2015-Jul-24, 05:57 PM
Clev, just so you know, I'm not trying to beat up your idea. I love a good gaming/story world.

I was talking about the equatorial regions. Plus all that sunlight pumping gigatons of water vapor into the air. I'd say, oh, roughly twice as much as what occurs on Earth.

The poles could be home to all manner of advanced fungoids.

There's your major plot line right there, a race of sentient mushrooms.:)

As far as having a much weaker magnetic field, it's possible that Mars lost most of its atmosphere due to erosion from the solar wind after its core froze and stopped generating a powerful field. I'm not sure if that would apply to a much larger planet with stronger gravitation.

grapes
2015-Jul-25, 01:46 PM
How slow? Too slow and your magnetic field won't be strong enough to effectively protect the surface of the planet from the local suns "wind".
The rotation of a planet is not directly responsible for the generation of its magnetic field. For instance, most of the earth's magnetic field is produced halfway down, near the core-mantle boundary, and even the differential rotation between the core and mantle is very slow.

Noclevername
2015-Jul-25, 10:28 PM
Clev, just so you know, I'm not trying to beat up your idea. I love a good gaming/story world.

I was talking about the equatorial regions. Plus all that sunlight pumping gigatons of water vapor into the air. I'd say, oh, roughly twice as much as what occurs on Earth.

The poles could be home to all manner of advanced fungoids.

Why twice? The Earth doesn't have that much equatorial land. And if I move the planet further out from the sun, the equator will be cooler.

:doh::doh: D'oh! Day's twice as long. OK, forget I said anything ever. :doh::doh:

Noclevername
2015-Jul-26, 12:52 AM
Wait, there'd also be twice as much cooling time, right? Wouldn't that take a lot of moisture out of the air?

John Mendenhall
2015-Jul-26, 04:07 AM
Wait, there'd also be twice as much cooling time, right? Wouldn't that take a lot of moisture out of the air?

Oh yes. I think you need a way to buffer the night/day temperature change.

Noclevername
2015-Jul-26, 04:55 AM
Oh yes. I think you need a way to buffer the night/day temperature change.

How? Have the oceans full of mirrored seaweed? :)

Inclusa
2015-Jul-26, 05:20 AM
Does the continent get quite south as well due to its sheer size?

Noclevername
2015-Jul-26, 08:13 AM
Does the continent get quite south as well due to its sheer size?

Into the equivalent of the Temperate zone, by my estimate.

Darrell
2015-Jul-27, 03:03 PM
The rotation of a planet is not directly responsible for the generation of its magnetic field. For instance, most of the earth's magnetic field is produced halfway down, near the core-mantle boundary, and even the differential rotation between the core and mantle is very slow.

From what I understand relatively weak magnetic fields can even be produced by interaction between the atmosphere of a planet and the solar wind. But the more typical magnetic field generated by a dynamo at the core of a planet supposedly requires three things. A conducting liquid, rotation and convection. According to currently used models of planetary dynamos rotation is a significant factor. Generally speaking, and the other two major factors being constant, faster rotation will result in a more powerful magnetic field and slower rotation a less powerful field. According to current models.

Venus is a good example of all of these things. Its weak magnetic field is of the kind that is produced by interaction between its atmosphere and the solar wind. It does not have any appreciable field generated by a dynamo at its core. Yet it does (it is thought) have a conducting liquid core. But, it has a very slow rotation and (relevant to your point) it is thought that there is no convection between a hotter core and cooler mantle as evidenced by the apparent lack of tectonic activity, which is also driven by convection.

John Mendenhall
2015-Jul-27, 03:52 PM
How? Have the oceans full of mirrored seaweed? :)

CO2? This could get really tricky. Any climate experts out there on the forum?

Another thought, how about a permanent cyclonic storm a la
Jupiter's Great Red Spot, due to intense ocean insolation. It could drift along between the continent and the equator . . . occasionally touching the continent . . . winds at 250 to 300 mph . . .

Sign me up for the colonizing interstellar FTL ship!

Noclevername
2015-Jul-27, 06:45 PM
CO2? This could get really tricky. Any climate experts out there on the forum?

Another thought, how about a permanent cyclonic storm a la
Jupiter's Great Red Spot, due to intense ocean insolation. It could drift along between the continent and the equator . . . occasionally touching the continent . . . winds at 250 to 300 mph . . .

Sign me up for the colonizing interstellar FTL ship!

There's no ship in this story, it's a stable wormhole transport. The coastlines are not habitable due to the native life (a toxic algae-analog)

starcanuck64
2015-Jul-27, 06:52 PM
CO2? This could get really tricky. Any climate experts out there on the forum?

Another thought, how about a permanent cyclonic storm a la
Jupiter's Great Red Spot, due to intense ocean insolation. It could drift along between the continent and the equator . . . occasionally touching the continent . . . winds at 250 to 300 mph . . .

Sign me up for the colonizing interstellar FTL ship!

Water vapor is the main component of the greenhouse effect, so having the part of the planet that receives the greatest insolation open water is going to mean a lot of evaporation and a greater greenhouse effect. Lowering the CO2 might help a bit. I think you'd also have some pretty good winds and storms along the day/night terminators, think of them as permanent storm fronts where hot high humidity air collides with cooler dryer air masses.

Jeff Root
2015-Jul-27, 11:11 PM
I don't understand why Earth doesn't have permanent storms
following the sunset terminator. We had plenty of water vapor
in the air last night to condense into clouds and rain, but it
didn't. It felt like it got warmer after dark! Although maybe
that was just me.

-- Jeff, in Minneapolis

John Mendenhall
2015-Jul-28, 12:18 AM
There's no ship in this story, it's a stable wormhole transport. The coastlines are not habitable due to the native life (a toxic algae-analog)

Which can be blown inland by large storms . . .

Hey, you've got a great idea going !

Noclevername
2015-Jul-28, 12:37 AM
The difficult part is getting Earth life to grow in the local ecology. Right now there's just enough food to support the human population, most of it growing in a single valley that is just below sea level. I wonder what could happen?... :think: