Ice/Desert/Jungle planets

[Damburger]

A common sci-fi cliche that gets pointed out is that alien planets seem to have a single climate. I've got to ask though, is this really such a bad thing?

Earth is unusual I think in the amount of variation there is. The pressure, temperature, and amount of sunlight varies an incredible amount on the surface of the Earth (so long as you include the seabed as part of the surface and the oceans as part of the atmosphere).

Look at the other planets in our solar system. You don't get 100 fold variations in pressure on the surface of Venus. You get a pretty consistent amount of sunlight on Mars. Is it so unreasonable to suggest that you don't have to have a massive range of environemental conditions on every planet that occurs in science fiction?

[The Supreme Canuck]

I can see desert and ice planets happening, but I'm not so sure about the rest. I think this was discussed elsewhere, now that I think of it...

[Dark Helmet]

I always imagined Tatooine being on the inner edge of the Life-Belt, Hoth being on the outer edge. and Dagobah being on closish to the inner edge.

[eburacum45]

Earth-like planets, if any exist, will be very variable;
temperature range and position within the habitable zone will affect climate, so will axial tilt; very important as well will be the ratio of water to land.

A world with ten percent water cover will be very dry almost everywhere, and will have a continental climate with wide variations in temperature over a year and also over the length of a day. Of course it will be colder at the poles, but summer days on such a dry world could get hot even at high latitudes.
A world on the other hand with 10% land would have a maritime climate almost everywhere, and it is quite possible that no ice cap would form even on cool worlds because currents would be too active.

A water world would probably habe permanent equatorial curerents racing round the planet unopposed; there might be more winds on a smooth obstruction-free waterworld as well, but perhaps not covering every part of the globe.

Incidentally, a world in the grip of an ice age may well have a warm tropical region; how do you suppose lions and crocodiles and zebra survived the last few glaciations? Hoth would probably be a rare snowball Earth type, waiting for volcanic CO2 outgassing to build up enough to melt the ice once more.

[SkepticJ]

I always imagined Tatooine being on the inner edge of the Life-Belt, Hoth being on the outer edge. and Dagobah being on closish to the inner edge.

But is there really such a thing as a life belt? If earth had more CO2 it could be farther from the sun. If earth had more ice to reflect sunlight it could be closer than it is to the sun. What about large rocky moons orbiting a brown dwarf super gas giant that is as far from its parent star as Saturn is to Sol? What about Europa? It's not sunlight that gave Europa an ocean. What about caves on a rocky world 8AU from its star that have hydrothermal springs welling through the cave floor?

[eburacum45]

But is there really such a thing as a life belt? If earth had more CO2 it could be farther from the sun.
That would not be a very Earth-like world, but perhaps possible. The habitable zone is probably quite a bit broader that generally supposed, especially if you include life-bearing but not very Earth-like worlds.
If earth had more ice to reflect sunlight it could be closer than it is to the sun.
Nearer the star but with more ice? perhaps not so likely.
What about large rocky moons orbiting a brown dwarf super gas giant that is as far from its parent star as Saturn is to Sol?
Life on such a world would probably inhabit the brown dwarf's magnetic field, possibly full of energetic particles. But perhaps not entirely impossible.
What about caves on a rocky world 8AU from its star that have hydrothermal springs welling through the cave floor?
Also interesting idea, but what would the climate be on such a world?

[SkepticJ]

What about caves on a rocky world 8AU from its star that have hydrothermal springs welling through the cave floor?
Also interesting idea, but what would the climate be on such a world?

Lots of different things it could be like. Bone dry and cold like Mars. Near 0 kelvin and has a thin methane atmosphere like Titan etc. Maybe it would be even farther from the star(s) and have oceans of liquid helium or nitrogen. The caves would be closed to the surface and several km underground. Maybe there would even be plants with broad leaves that use IR radiation from the hot water instead of the wavelengths that earth plants use for photosynthesis. Animals "see" by echolocation, or maybe they have evolved a bioluminescent light bulb and have big sensitive eyes. Smell and touch work in the dark well to.

[SkepticJ]

Sorry about killing this thread.

I see no problem with ice planets and desert planets; we have them here in this solar system. Pluto and Mars. Aqua planets seem likely to me also. The Earth is 70+% water. It would be interesting to see what kind of life evolves on a world that only has small scatered islands or is totally water. Jungle planet, hmmm, the atmosphere would probably have to have several times the CO2 that Earth had in the Jurassic Period. Perhaps most of the planet's land could be jungle, but the poles would be a bit cooler if the axis is perpendicular to the plane of orbit, perhaps "grass" lands could be there.

[Swift]

...It would be interesting to see what kind of life evolves on a world that only has small scatered islands or is totally water. ...
http://www.dacre.org/flash/www/gbq05901.jpg
8-[

[ToSeek]

Sorry about killing this thread.

I see no problem with ice planets and desert planets; we have them here in this solar system. Pluto and Mars. Aqua planets seem likely to me also. The Earth is 70+% water. It would be interesting to see what kind of life evolves on a world that only has small scatered islands or is totally water. Jungle planet, hmmm, the atmosphere would probably have to have several times the CO2 that Earth had in the Jurassic Period. Perhaps most of the planet's land could be jungle, but the poles would be a bit cooler if the axis is perpendicular to the plane of orbit, perhaps "grass" lands could be there.

Uniform lifeless environments are reasonable (desert planets, ice planets, etc.); uniform environments with life are difficult to justify, however (forest planets, jungle planets, swamp planets, etc.).

[Madcat]

I think it's worth pointing out that ice planets would technically also be desert planets. :wink:

[Dark Helmet]

Although, Hoth IS described as fairly lifeless.

And you don't see many native species walking around on Tattoine. and I think that most of the events in the films are probably in the polar areas as the equatorial areas are most likely to be inhostpitable to life

Luke many have just gotten un/lucky with where he landed, they only show the swamp that Yoda lives in, the whole planet may not be like that. just that dense equatorial area.

However, there is a large amount a cloud-cover shown over the planet, meaning that they could be a large amount of greenhouse gasses in the atmosphere. More likely to be water vapor from both transpiration and the regular hydrologic cycle. rather that CO2

Dagobah seems loke a hot planet, but not too hot for liguid water.

[SSJPabs]

Well you'd allow for SOME variation, but could a jungle planet say, have only a very small temperate zone so that the majority of the planet is either jungle or polar?

Personally I'm working on a jungle/
semi-arid/icy type world but its slow going since I have a lot to learn.

[eburacum45]

One idea is to look at our own planet at various times in the past; during the Cretaceous, for example, there were forests within the arctic circle... a planet warmer than ours could be a mixture of tropical rainforest, temperate forest and various types of desert,

while even a world in the midst of an ice age could easily have hot tropical rainforests, as our own planet does during glacial periods.

A planet with primitive lowlying vegetation could look like a desert, even if it is not, because the ground cover would be insufficient to retain water.
And so on.

[Maha Vailo]

I could imagine a real-life swamp planet. It would probably be an Earth-like planet on which all mountain-building/tectonic activity has ceased, and erosion has worn everything to lowlands.

Jungle planets or forest planets? Probably not. Even if the planet's axis was straight up or nearly so, you'd still have climactic zones of some sort - eternal winter (icecaps) at the poles, eternal summer (desert? jungle?) in the tropics and eternal spring/fall (anyone have any idea what a similar climate on Earth would be? I don't know), which would greatly affect the types of plants and animals that lived there. Then there's the effects of seas, mountains, large land masses, etc. on climate.

Just my 2 cents here. feel free to comment.

- Maha "strange new worlds" Vailo

[Eroica]

Snowball Earth (http://www-eps.harvard.edu/people/faculty/hoffman/snowball_paper.html)
8)

[ToSeek]

I could imagine a real-life swamp planet. It would probably be an Earth-like planet on which all mountain-building/tectonic activity has ceased, and erosion has worn everything to lowlands.


But it would be hard to have swamps at the poles - they'd freeze!

[Ut]

Nah. Obviously, the swamp planets have dealt with hundreds of years of industrial atmospheric pollution. The greenhouse effect keeps everything nice and toasty. And wet.