It's just another fraction to multiply in the drake equation. Start with planets, cut down to rocky ones, only in habitable zone, only rotating a certain way, o

It's just another fraction to multiply in the drake equation. Start with planets, cut down to rocky ones, only in habitable zone, only rotating a certain way, only with plate techtonics, etc etc. Or using your numbers, 1/4 factor eliminates 750 million possible candidates. That's not a happy thought.