OP back atcha' Notice I said.... "Nowhere else in the all the vastness of the universe is life known to exist." It likely does or has or will harbor life. Just presently unknowable. The universe is also temporally vast. Life may have existed elsewhere a million or a hundred million or a billion years ago and long since has gone extinct. Once our sun runs out of fissionable elements there will, quite likely, be not a trace of our earth or civilization ever having existed but there just may be sentient life newly evolved somewhere out there wondering if they are unique and alone in the universe!!!