the fact that if the strength of gravity differed from its known strength by as much as one part in 1 × 10"40, stars like our sun could not exist, and therefore neither could a life-supporting planet like earth.

 the fact that if the strength of gravity differed from its known strength by as much as one part in 1 × 10^40, stars like our sun could not exist, and therefore neither could a life-supporting planet like earth.