Alien life could be shielded by seas or smog

摘要

THOUGH they seem inhospitable, red and white dwarf stars could host planets with life forms. These stars have narrow habitable zones - the areas around them where planets could have liquid water -yet their prevalence makes them tempting targets in the search for life. Any planet in such a star's habitable zone is close enough to be tidally locked into a perpetually blazing dayside and frigid eternal nightside or, worse, shredded by tidal forces. "If you park a planet in a habitable zone around a white dwarf, it will stay there for a very, very long time -potentially enough time for life to manifest. The problem is getting [the planet] there," says Jason Nordhaus at Rochester Institute of Technology, New York.