In the cosmological context, for the Standard Model to be valid up to the scale of inflation, the top quark Yukawa coupling y (t) should not exceed the critical value y (t) (crit) , coinciding with good precision (about 0.2aEuro degrees) with the requirement of the stability of the electroweak vacuum. So, the exact measurements of y (t) may give an insight on the possible existence and the energy scale of new physics above 100 GeV, which is extremely sensitive to y (t) . We overview the most recent theoretical computations of and the experimental measurements of y (t) (crit) and the experimental measurements of y (t) . Within the theoretical and experimental uncertainties in y (t) , the required scale of new physics varies from 10(7) GeV to the Planck scale, urging for precise determination of the top quark Yukawa coupling.