Comment by hparadiz
Comment by hparadiz 21 hours ago
I always wonder what would happen if you put a fully enclosed glass terrarium in space. How would it fair. Not big either. Grape fruit sized.
Comment by hparadiz 21 hours ago
I always wonder what would happen if you put a fully enclosed glass terrarium in space. How would it fair. Not big either. Grape fruit sized.
That's not how space or terrariums work. A terrarium does not spontaneously produce energy out of nothing, it gets energy from the sun. Heat input from the sun is proportional to cross sectional area, while heat loss to space is proportional to surface area, which scale the same for a sphere. A larger object will have more thermal mass which would make it take longer to change its temperature, but it will still have the same thermal equilibrium. Terrariums do not need to be spheres, so the volume does not necessarily scale as the radius cubed.
I imagine one like that in my kitchen which is currently moss, a succulent, and some weed that happened to germenate. All three are alive after two years so far. The bottom is rocks and soil. There's a clear water cycle too as water evaporates and collects on the surface of the glass and then drips down.
Heat isn't produced by the volume. Heat may be produced by something within the volume, but it's not the volume's existence that causes heat to be produced. There is no fundamental reason a bigger terrarium should produce more heat, nonetheless that heat production should be directly proportional to volume.
Giant terrariums in space was the premise of one of the great science fiction films of the early 1970s: Silent Running
Sphere's surface grows as radius squared, but volume grows as radius cubed. Hence a small terrarium will quickly freeze, and a huge terrarium will eventually fry. There is an optimal size for a terrarium, given its orbit, that keeps its internal temperature within the habitable range.
Also it would need many more plants than animals. I would rather go with an aquarium.