I'm not sure how scientists determine that a planet is really an Earth-like planet. How do they do it?
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 ...
I have heard that the only planets able to be seen outside the Solar system are Jovian-sized planets with the occasional detection of planets three times the Earth's size. But, as far as I know, we ...