June 8, 2011

Planets Outnumber Stars

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--unbound exoplanets that do not orbit any star--are so numerous that they outnumber the stars!

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 include all the exoplanets that are hosted by stars, and does not even count rocky exoworlds that are less massive 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 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)
Unbound or Distant Planetary Mass Population Detected by Gravitational Microlensing (arXiv)

1 comment:

Anonymous said...

Knowing that theoretically there should be more rocky planets than Jupiter-sized planets... Things are getting really fascinating!

To quote Sagan one more time:

"Somewhere, something incredible is waiting to be known."