The idea that galaxies are littered with wandering planets is truly exogasmic. For quite some time I’ve been wondering whether planets outnumber the stars. Then the answer came which truly blew my mind away.
Evidence has been revealed that rogue planets--those exoplanets that do not orbit stars--are so numerous that they outnumber the stars themselves.
Using the method called Gravitational Microlensing, it has been estimated that 400 billion rogue planets roam the Milky Way. Take note, the estimate does not yet include all the exoplanets that are hosted by stars, and does not yet count all the rocky exoworlds smaller than Jupiter. And remember that this comes after the fact that red dwarf stars were found to be more numerous than previously thought. Add them all and you've got gazillions of exoplanets in the cosmos!
Do you remember when Carl Sagan mentioned that the stars outnumber the all grains of sand on all the beaches in the world? Well, perhaps we need a new metaphor that includes not just the beach but the desert as well. Because planets outnumber all the grains of sand on Earth!
Rogue Planets (Centauri Dreams)
Milky Way Harbors Billiions of Orphaned Planets (AstroBob)