A magnetically suspended ball containing a steel globe which, using pillars, supports a glass globe filled with water. A relief globe of the planet is embossed on the surface containing forests of algae or bryozoa, while the water contains plankton, forming a self-contained ecosystem.-- nineteenthly, Oct 27 2009 Ecosphere http://en.wikipedia...Ecosphere_(science) [xaviergisz, Oct 27 2009] Incidentally, has this been posted before?-- nineteenthly, Oct 27 2009 I think that a self-contained ecosystem is relatively easy to make: put almost anything in a bottle and close the lid. Some kind of life will find a way of existing in there (probably just slime and mold).
So the question becomes: what is the minimum size for a self-contained ecosystem to support visually interesting and complex life forms?.
Ah, I've just answered my own question; see Ecosphere link.-- xaviergisz, Oct 27 2009 Here's a snippet of the wikipedia article: Every manmade closed system inevitably degrades. The EcoSphere and comparable closed systems are actually "self-sustaining" only in comparison to systems which degrade much more quickly. In any closed, unfiltered, unaereated aquarium, it must be expected that the larger organisms will reach the end of their lifespans, die, and pollute the water with a sharp influx of decay products; or the nutrients in the food cycle will gradually get "locked up" in unusable forms; or the pH of the water will fall outside the survival range of the organisms.-- xaviergisz, Oct 27 2009 I think we would too...-- theleopard, Oct 27 2009 We second that.
Would it have volcanoes ? There should be volcanoes ....-- 8th of 7, Oct 27 2009 Yes, it will run down eventually, but that would depend on the size. You could maybe cheat and have stuff inside the globe. It also makes me wonder about those wheel in space colonies, which would also run down similarly.[UB], i did come up with a planet of one's own at some point but i can't track it down, a problem with which i expect you are very familiar.Right, volcanoes. Yes, it can have volcanoes, and of a very special kind - ketchup. You shake the globe to get it going and it provides nutrition, the problem being the acetic acid in the tomatoes and the sauce. But, you then have a spherical lava lamp into the bargain, and the ketchup becomes a form of input.-- nineteenthly, Oct 27 2009 wot no turtles?
that reminds me I need to add Pratchett to a certain list.-- po, Oct 27 2009 I'd bun this but the title has put The Seekers in my head and they won't leave.-- shudderprose, Oct 27 2009 I'm sure I've got one of those sea monkey ads kicking around here somewhere...-- 2 fries shy of a happy meal, Oct 27 2009 random, halfbakery