There's some truth to that. Europa, Enceladus, and other places are more than frozen ice balls because they get tidal heating from orbiting a gas giant. Even so

There's some truth to that. Europa, Enceladus, and other places are more than frozen ice balls because they get tidal heating from orbiting a gas giant. Even so, there are probably vast amounts of rogue gas giants between the stars. The very largest of these objects are known as brown dwarfs.