Earth has a water cycle , Titan has a methane cycle . That doesn ’ t mean that it can ’ t evolve to one day be like Earth . But sadly , despite having no clear yes or no answer , the odds certainly aren ’ t in our favor for a breathable atmosphere , not only because there is likely no surface water , but also because there would ’ ve already been life .
After all that , let ’ s think about Earth and take a deep breath . All this talk of poison and crushing atmospheres is making me homesick .
What are two places where we might be able to breathe outside the solar system ? First , let ’ s start closer to our home , Earth , and by close I mean 4 light years away . A light year is the distance light moves in a year . This is Proxima Centauri B , a super earth that is approximately 1.27 times the size of Earth . Proxima B orbits a dim red dwarf star . Although Proxima B is in the center of its star ’ s habitable zone , Proxima Centauri A ( the star ) is too active and releases solar flares — or giant brief eruptions of intense high-energy radiation from a star ’ s surface — straight into the atmosphere , destroying Proxima B ’ s chance to have water , life , and most importantly for this topic , a breathable atmosphere . However , Proxima B ’ s atmosphere isn ’ t totally gone and may still have just enough oxygen and nitrogen for humans to breathe on . By far , Proxima Centauri B has the highest chance of a breathable atmosphere .
But enough of that , it ’ s time to go just a little bit further to GJ 1214B . Once again what I mean by just a little bit more is 40 light years away . GJ 1214B is a Neptune-like ice giant , and although it is incredibly out of the habitable zone , its surface may not totally be out of ice . Now , if you somehow don ’ t know what I mean , due to GJ ’ s mass and heat , the ice may have melted , leaving an almost completely liquid water surface .
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