No shortage of speculations as to where ET life might be hiding. From Mike Wall at LiveScience:
E.T. may be out there, silently swimming in frigid oceans beneath miles and miles of ice.
Last week, planetary scientist Alan Stern offered up another idea: Maybe intelligent life is widespread throughout the galaxy but most of it lives in deep, dark subsurface oceans that are cut off from the rest of the cosmos.
For starters, Stern said, such buried oceans may be common across the Milky Way. Indeed, they should be, if our own solar system is any guide: Liquid-water oceans slosh beneath the frigid shells of the Jupiter moons Callisto, Ganymede and Europa, for example, as well as the crust of the Saturn satellite Enceladus. And buried oceans are suspected to exist on a number of other worlds, including Pluto and Saturn’s biggest moon, Titan. (The only world known to have a water ocean on its surface is our own Earth.) … More.
Sounds interesting, and it is an idea that can be tested in the foreseeable future. Not so sure about some of the ones below:
Speculations to 2013:
More often we are just told that we lack imagination, we have searched too narrowly: Moonless planets have been unfairly dismissed and sunless ones could maybe ferry life around the galaxy. Some argue that hardy Earth life forms could have made it to one of Jupiter’s moons and survived there. Jupiter’s moon Europa looks promising to many. NASA has talked of a “flying-saucer-shaped space boat” to Saturn’s moon Titan, some day. And the excitable word about another Saturn moon is, “Enceladus Now Looks Wet, So It May Be ALIVE!”
Exoplanets orbiting red dwarfs at a distance, it is said, may counterintuitively support life. So might exoplanets’ moons. Every month, we hear of a planet or moon capable of supporting hype.
More exotically, some seek life around failed or dying stars. If that doesn’t work, dark matter could make planets habitable (though we don’t yet know what dark matter is). And, should the laws of physics vary from place to place, life elsewhere might follow different laws. In that case, should the physics term “constant” be changed to “local variant”?
Lastly, encountering hard, doubting hearts, alien life proponents resort to moralizing: An editorial preaches “Uniqueness seems rather too presumptuous a claim for one small planet in an undistinguished corner of a vast cosmos.” Our vaunted respect for evidence is a mere cloak for pride and presumption!
See also: Don’t let Mars fool you. Those exoplanets teem with life!
How do we grapple with the idea that ET might not be out there?