Top 5 Habitable Alien Planets - here we have examples of planets located within the habitable zone, for just one star. There are billions of stars out there. So the idea of the non-existence of extra-terrestrial intelligent to be highly absurd.
This diagram compares our own solar system to Kepler-22. Kepler-22's star is a bit smaller than our sun, so its habitable zone is slightly closer in. The diagram shows an artist's rendering of the planet comfortably orbiting within the habitable zone, similar to where Earth circles the sun