Does a self sustaining ecosystem aquarium/zoo exist? I mean like a closed space with a few different kinds of animals that sustains itself without an external food supply. Of course I’ve heard of a few lakes that only have water coming in and out, but what is the minimum size of a body of water or piece of land that can sustain a non-trivial amount of life?
We like to think of ‘cold’ as the lack of heat. Why? Because there is a minimum of heat, or you could say a maximum of cold. But actually there’s also a maximum of heat, though it probably would be hard to reproduce in a lab. The maximum temperature is what you get when you make all the particles in the world explode thus summing up all their energies into one particle. That one last surviving particle that contains all of the universe’s energy, it’s temperature is MAX_T. So maybe this whole ‘there is no cold’ fiasco was a simplification of the real situation. Hot/cold is just a scalar with two end-points, call it heat, call it coolness, whatever.