Abstract
In this paper we have discussed the radius of the habitable zone for exoplanets. The universal formula for the radius of the habitable zone is obtained. The radius depends only on the fine structure constant for electromagnetic interactions and the ratios of the Planck mass / proton mass, and proton mass/electron mass. For the present Epoch the width of the habitable spherical shell is of the order of 0.8 AU. In the future , in the case of Doomsday Humanity can escape the End by changing the values of Nature constants
MIROSLAW KOZLOWSKI