Of all possible universes, ours is probably not the only inhabitable one. Universes that start under different circumstances from our own might give rise to a wide range of exotic habitable environments, researchers suggest May 24 online at arXiv.org.
As if our universe weren’t large enough, some researchers speculate that it might be embedded in an even grander network dubbed a multiverse, where each universe operates under its own laws of nature. The most fruitful universe for life as we know it might be one with galaxies where the stars are crammed together too closely for planetary systems to hold together. The outskirts of those same galaxies, however, could host hordes of free-floating worlds (SN: 4/4/15, p. 22) that are kept warm and cozy by the light from millions of neighboring suns, astrophysicist Fred Adams of the University of Michigan and colleagues report.