re: What if you could come up with a molecular structure that would cause a greenhouse in reverse?
Stop the light/heat coming in, but still let the heat radiate out?
It would almost certainly require clouds of molecules that are completely foreign to that region of space but in some way self-replicating.
A chemical process similar to DNA? What about relocating life forms from deep sea hydrothermal vents to the upper atmosphere of Venus?
Just trying to think WAY, WAY, Outside the box.