  Recently it was demonstrated that the theoretical predictions for the Planck
scale space-time fluctuations derived by the simultaneous consideration of
quantum mechanics and general relativity fail by many orders of magnitude
against the stellar interferometry observations. We propose the explanation of
this puzzle based on the short distance modification of gravity. Roughly
speaking the criterion of this modification to fit the astronomical
observations is that the gravitational radius of the mass as large as $\sim
10^{26}$kg should not exceed $\sim 10^{-36}$cm. From this point of view we
consider the modification of Newtonian inverse square law due to Yukawa type
correction and the modification due to quantum gravitational corrections
obtained in the framework of nonperturbative RG approach. The latter one does
not satisfy the required criterion for modification.
