A planet 20 light years away is the first outside the solar system to be officially declared habitable by European scientists.
The ‘exoplanet’ Gliese 581d has conditions that could support Earth-like life, including possible watery oceans and rainfall, they say.
Yet any future space voyagers landing there would find themselves in truly alien surroundings.
The sky is likely to be murky red, not blue, gravity is twice that of Earth, doubling the weight of anyone standing on the surface, and the carbon dioxide-rich atmosphere would almost certainly not be breathable by humans.