When did Tycho Brache come onto the planet earth ?
In Heinlein 's short story " Blowups Happen " , a character hypothesizes that Tycho may have been the location of a sentient race 's main atomic power plant , in a past time when the Moon was still habitable — and that the plant exploded , causing the craters , the rays spreading from Tycho , and the death of all life on the Moon .