Do galaxies have habitable zones the same as stars do? Say in a galaxy with a very active nucleus producing a lot of heat and radiation, would there be a point at which no star's planets could harbor ...
At present, it seems like we are alone in our solar system. How many earth-like planets would fit into the habitable zone of the solar system? The orbits should be stable for quite a time, i.e. for ...
Could Earth-like (suitable for Human habitation) planets exist in systems with 2 or 3 suns, have any been found? With more than a single star, isn't it likely that the habitation zone would be too ...