Long before they helped craft Earth's first soils, fungi may have traveled the universe in rudimentary spaceships made of rock. Izzie plunges into the science of sci-fi mycology, breaking down the impossible mission of microbes in space and laying out some of the evidence for - and against - the idea that we Earthlings are not alone.    Introduction transcript: “Space. The final frontier. These are the voyages of the Sporeship Enterprise. Its continuing mushroom: to ex-spore strange new worlds. To seed out new life and new lichenizations. To moldly go where no one has gone be-spore!"