white dwarfs do emit enough light and heat to have a habitable zone. But the question remains as to whether a planet could retain a water-rich environment through the red giant stage of a star ...

A new world has just been found orbiting a Sun-like star only 20 light-years away, and it could be one of the most promising ...

Within a billion years, a runaway greenhouse effect will likely vaporize Earth’s oceans, making the planet uninhabitable long before the sun’s red giant phase. As the sun’s habitable zone ...