Wanderers Between the Galaxies

by PAUL GILSTER on OCTOBER 25, 2012

The idea of planets outside their normal settings is unsettling. It implies that beyond the stars all around us there may be worlds without suns, dark planets presumably pushed there by gravitational instabilities in their home systems. We’ve looked at such ‘nomad’ worlds before, noting that ice overlaying a frozen ocean might trap enough geothermal heat to create life-sustaining conditions. Estimates on how many such planets might exist vary widely, but in one recent paper Louis Strigari (Stanford University) has calculated that 105 objects larger than Pluto may exist for every main sequence star (see Island-Hopping to the Stars for more on Strigari’s work on free-floating planets). Survey missions like Gaia may help us find some of these.

Read more: Wanderers Between the Galaxies — Centauri Dreams.

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