Imagine a Floating Continent the Size of Russia

[Dragon Angel]

I am currently writing a story which involves, as the subject says, a floating continent approximately the size of Russia today. Its atmospheric position is...let's say, about 8,000+ meters up from the Earth's surface (almost reaching the stratosphere), and it has a mean thickness of perhaps 45km throughout its body (this is an extremely rough figure - a better number would be helpful).

Put simply, taking aside all the magic-tech that it requires to even exist, what would the side effects be of such a body floating this close to the Earth?

[Dragon Angel]

Oh, and to add one more important point that was brought up: It remains more or less stationary in its position. If it does move, it only does so very slightly (perhaps only a few meters in the single - low double digits).

Otherwise, it is pretty much fixed in the atmosphere.

[Mr Bean]

Oh, and to add one more important point that was brought up: It remains more or less stationary in its position. If it does move, it only does so very slightly (perhaps only a few meters in the single - low double digits).

Otherwise, it is pretty much fixed in the atmosphere.

Well the area underneath would be in perpetual night of course obvious one. Sunlight (Which I don't want to run the math) means that anywhere more than 39 kilometers under the mass won't get any direct sunlight ever and refracted sunlight (Again don't want to run the math) means roughly anything more that 70 kilometers in is for all intents and purposes midnight with you getting closer to black the further you go under the mass.

You getting into some very weird atmospheric effects as well as what you describing is in essence a land that is 100% "Mount Everest Peak" conditions without the mountain to go under it.
Look into what they call the "Death zone of Everest" to get an idea of the condition of this entire landscape of floating rock would be like baring more magic.

[madd0ct0r]

presumably the eternal night under it would create a permanent downdraft.

So at ground level there'd be a wind blowing away from it nearly constantly. Likewise, you'd have the upper atmosphere blowing towards it, so I suppose you'd get significant changes in weather patterns.



Is it on the equator or above a pole?

I assume the skyhooks it is using don't have any side affects themselves.

[Akhlut]

Regardless of where it is, it is an enormous disruption of bird migratory routes. Depending on how long the floating continent has been around, it has either produced massive die offs of certain bird species, or every species in the world avoids the floating continent like the plague.

Further, due to so much area being devoid of light, one would see a drastic reduction in plant life. Unless the floating continent has vast numbers of plants on it, there's going to propotionately be much less oxygen and much more CO2. I don't know what sort of calculations I'd need to do for that, but it's probably going to be vast. That in and of itself is probably going to have some very large ecological concerns. Also, whatever parts of it are over the ocean are going to reduce the amount of plankton growing under it and are going to lower ocean productivity. This would mean fishing is less stable, among other things. I imagine one would see a large ice cap under the continent, too, in the ocean, but I don't know if it would get cold enough to do that.

There's also the problem that this giant rock is going to screw with surface albedo and could quite possibly lower global temperatures fairly significantly.

[Solauren]

What would happen if this contient, on Earth, was over the center of the Pacific ocean?

[madd0ct0r]

Oooh!

Precipitation.

While I'm not so sure what'd be happening on the topside (Lichen?) the underside of the rock would be bloody cold. Couple that with the downdraft effect and you could get a rather cool giant ice stalactites.

there's a fascinating paper here on icicle formation:
http://www.igsoc.org/journal/34/116/igs ... g64-70.pdf

It suggest that under the windy conditions we're looking at, you don't get icicles forming, instead you just get a blanket of ice (Presumably similar to the inside of a freezer). The point is it the wind makes the water freeze to quickly and it is then unable to travel to the tip.

here may also be of use: http://www.jstor.org/stable/2666835?seq=8

So, not icicles, and because Ice has a finite tension strength no single giant upside-down mountain of ice.
(probably. I'm suddenly feeling that ice may be plastic enough to redistribute force around weak spots, with the limit then being the bond to the underside of the rock)

Since the sides of the rock will be warmed by the sun, and may have rain running down them occasionally, I'd expect the 'frost' to melt back from the edges, creating a thick ridge of ice a little way in from the edge. This ridge would build up slowly until too heavy, then a chunk would fall off.

I'm not sure, the scale is far beyond anything I've considered before, but this ridge might mean the air against the rock inside the ridge boundry would not be refreshed by the incoming air for the downdraft. Thus frost build up towards the center of the plate might be very slow indeed.

The earth's drinking water is safe.

[madd0ct0r]

What would happen if this contient, on Earth, was over the center of the Pacific ocean?

assuming my guess over the wind pattern is correct, you'd get some killer waves all around the pacific rim.

[Ilya Muromets]

Another interesting possibility to consider, if this thing is over land, is the kind of biology you could find under the shadowed area. Assuming, just for the sake of argument, that this floating continent also drifts across the sky in as painfully slow a rate (or just slightly faster) as the continental drift of terrestrial land. This would mean that once unshadowed areas would, eventually, find themselves under the permanent shadow of the sky continent.

Seeing all the weird little creatures which developed in the light-less environment of real life cave systems, one wonders what weird creatures might evolve in the ground under the continent's permanent shadow. Especially as there's more living space than a subterranean cave system.

[Lord of the Abyss]

Wouldn't the top of the continent be covered in ice too at that elevation? That would be enough ice to affect sea levels I'd think, like the Antarctic ice sheet.

[Surlethe]

This belongs in Fantasy, not SLAM.

[Zixinus]

Wouldn't the top of the continent be covered in ice too at that elevation? That would be enough ice to affect sea levels I'd think, like the Antarctic ice sheet.

There is also gravity. The water will come down wherever it can, unless the levitating continent is surrounded by hills higher than local water levels (which can bring problems inward).

I'm mostly imagining desolate frozen wastelands here with large strips of desert. At least, at those highs.

[Lord of the Abyss]

Wouldn't the top of the continent be covered in ice too at that elevation? That would be enough ice to affect sea levels I'd think, like the Antarctic ice sheet.

There is also gravity. The water will come down wherever it can, unless the levitating continent is surrounded by hills higher than local water levels (which can bring problems inward).

It would be snow, not rain at that height surely?

If you do get glaciers they would flow just as in Antarctica and elsewhere, no doubt; just slowly. It just occurred to me that you could end up with fairly common tidal waves from huge chunks of glacier calving off and falling into the sea 8000 meters down.

[Junghalli]

Guys the OP says the floating continent has "a mean thickness of perhaps 45km throughout its body". The top isn't going to be at Everest height, that's the underside, the top is going to be in space. My guess is it would have conditions roughly similar to the surface of the moon.

That might have interesting implications for a space program. You could theoretically reach the floating continent by aircraft and then climb into space (how steep are the sides?). The top would be a good place to put any industrial processes that require vacuum to work, as well as telescopes/observatories and eventually mass drivers (it's above virtually the entire atmosphere). It'd be a great place to do space launches in general as you no longer have to worry about atmospheric drag.

What would happen if this contient, on Earth, was over the center of the Pacific ocean?

Well for one thing it would probably raise Earth's albedo significantly, IIRC bare rock generally reflects more light than water. Couple this with the fact it's chilling a Russia-sized portion of ocean in perpetual shadow, and an equatorial part of the ocean at that, and I imagine the effect would probably be a significant cooling of the Earth in general. Quite possibly enough to put us into an ice age (or worse?). As far as climate goes, putting it over an equatorial ocean is probably the most disruptive place you could possibly put it.

Another interesting possibility to consider, if this thing is over land, is the kind of biology you could find under the shadowed area.

While the idea of surrealistic landscapes of fungi and weird eyeless creatures is cool, realistically I suspect the area underneath would probably be mostly a giant biological desert. Without sunlight there would be very little energy available to support an ecology. But hey, this thing already requires ridiculous magic just to exist, so maybe you could have magical based ecologies.

Wouldn't the top of the continent be covered in ice too at that elevation? That would be enough ice to affect sea levels I'd think, like the Antarctic ice sheet.

Assuming a top at 8 km (rather than 50 km) I kind of doubt it would get enough precipitation to have glaciers. I imagine the air at that level would be pretty cold and therefore dry, and isn't that height above most weather? Mountains that high on Earth have glaciers, but there you have the mountain to deflect moving moist air upward. This thing, moving moist surface air will just pass underneath it. So I could see the top being a gigantic cold desert, rather than glaciated.

[Werrf]

While the idea of surrealistic landscapes of fungi and weird eyeless creatures is cool, realistically I suspect the area underneath would probably be mostly a giant biological desert. Without sunlight there would be very little energy available to support an ecology. But hey, this thing already requires ridiculous magic just to exist, so maybe you could have magical based ecologies.

It depends if there's any geothermal activity under there - a continent the size of Russia, it's not unlikely there could be hot springs or volcanoes. All that's needed is some kind of energy input, we could easily see an ecosphere similar to that around black smokers in the ocean.

[Dragon Angel]

Heh... Hmm, 45km is definitely a little too thick for my purposes (obviously my sense of vertical scale was not functioning well yesterday). But yes, Jung is correct, in that the bottom-most point of my continent rests at Everest height, while its top side will be situated somewhere within Earth's lower stratosphere. I don't expect its top to be naturally habitable in any case, since all the habitable environment up there is completely artificial, and enclosed in a fashion similar to a bio-dome. There is still some surrounding, untamed land around this artificial environment however.

A better estimate of its mean thickness would probably be somewhere between 10-15km. Its length and width will still remain about the size of Russia. As far as where on the globe it is positioned, I will leave that as an open variable - either over land, or over the ocean, are both interesting situations. One way that you could use to imagine the shape of this continent is if you literally sliced a Russia-sized portion of land with a "cosmic knife" from the middle of Eurasia (or Russia itself, why not) and just scooped it up into the atmosphere.

[Junghalli]

It depends if there's any geothermal activity under there - a continent the size of Russia, it's not unlikely there could be hot springs or volcanoes. All that's needed is some kind of energy input, we could easily see an ecosphere similar to that around black smokers in the ocean.

Yes, you could have biological oasis fueled by geothermal energy. I imagine for the most part you'd probably be looking at a very barren landscape though, even if it has a habitable climate (it may not).

A better estimate of its mean thickness would probably be somewhere between 10-15km.

So the top is 18-23 km above sea level. This is above most of the atmosphere's mass and inside the ozone layer.

As far as where on the globe it is positioned, I will leave that as an open variable - either over land, or over the ocean, are both interesting situations.

The least disruptive scenario might be to put it in one of the polar regions - the areas are going to be cold and uninhabitable anyway. On the other hand you do reduce the planet's albedo this way, since you'll probably now have sunlight hitting desert instead of ice at the poles. This may warm the planet up.

One possibility you may have to worry about is the area beneath the continent becoming cold enough for CO2 frost. Since it never warms it would then become a black hole sucking CO2 out of the atmosphere, which if it went on long enough would kill plant life and possibly even lead to atmospheric collapse. You may want to consult somebody who knows more about this than me to see whether this is a reasonable possibility, but I've heard it speculated as a possible problem with tidally locked Earthlike planets (which are an analagous situation). According to papers I've read a .1 bar partial pressure CO2 atmosphere should prevent this, but this would not be breathable to humans.

Of course an obvious way to avoid this would be to have the floating continent rotate asynchronously with the rest of the planet, so instead of an area of perpetual darkness you'd have a band that's intermittently shadowed by it. That might be more interesting in some respects, as it's a lot easier to imagine animals and people being able to live there.

[Ilya Muromets]

While the idea of surrealistic landscapes of fungi and weird eyeless creatures is cool, realistically I suspect the area underneath would probably be mostly a giant biological desert. Without sunlight there would be very little energy available to support an ecology. But hey, this thing already requires ridiculous magic just to exist, so maybe you could have magical based ecologies.

That actually wasn't what I had in mind. I just like speculating on the kind of extremophiles that could tough it out in such an environment like they do in real life. Even a desert isn't completely lifeless after all, and even a few tiny, blind eyeless lizards or whatnot would be interesting to think about in a worldbuilding sense.

[Marko Dash]

whould lunar gravity have any effect on the continent?

[JointStrikeFighter]

no

[RedImperator]

While the idea of surrealistic landscapes of fungi and weird eyeless creatures is cool, realistically I suspect the area underneath would probably be mostly a giant biological desert. Without sunlight there would be very little energy available to support an ecology. But hey, this thing already requires ridiculous magic just to exist, so maybe you could have magical based ecologies.

That actually wasn't what I had in mind. I just like speculating on the kind of extremophiles that could tough it out in such an environment like they do in real life. Even a desert isn't completely lifeless after all, and even a few tiny, blind eyeless lizards or whatnot would be interesting to think about in a worldbuilding sense.

The desert isn't the right analogy, though. The only really good analogy to the environment under this continent is the abyssal plain, which is practically lifeless away from the black smokers. And unlike this environment, the abyssal plain at least has organic debris (fish shit and the occasional dead whale) drifting down from above.

[fgalkin]

In terms of darkness, yes, but in terms of temperature and pressure? And abyssal plains is some of the largest pockets of biodiversity on this planet (although, admittedly, much of it is microorganisms), so your point is moot anyway.

Have a very nice day.
-fgalkin

[Lord of the Abyss]

whould lunar gravity have any effect on the continent?

no

I don't know about that; I'd think something that large would be affected by tidal forces.