There could be moons as big as Titan, or even bigger than Ganymede that are as far as Jupiter or Saturn from their star. These moon do not get that much energy from their star.They actually get it from a Jupiter or Saturn size planet. A great example of such a phenomenon is the relationship between Io and Jupiter. Io is as hot as Venus because Io is not in the habitable zone of its planet, whereas Europa is. The pull betweenJupiter and its moons causes Io to be volcanic. If Io had a thicker atmosphere it could have had or have life. Problems: This could leave a giant areless moon in space.