
Earth may be our home, but another planet even cosier for life could be orbiting the star next door. A detailed analysis of what might make planets suitable for life says that
Alpha Centauri B, the star closest to our sun, would be the perfect star to host a "superhabitable" planet – a world of islands, shallow seas and gentle slopes, where the conditions needed to support a diverse array of life forms would persist for up to 10 billion years. But the near-paradise would come at a cost to visitors from Earth: the pull of gravity would be about one-quarter stronger than on our home turf.
We normally assume that the best places to look for alien life are Earth-sized planets orbiting sun-like stars. But our best models for habitability consider only a few criteria, such as the planet's size and distance from its star, seeking rocky worlds like Earth in similar orbits to our own.
"But no one had ever touched the question of whether other places may be even more benign environments than Earth provides,"(...)