Sunday, March 4, 2012

How Many Unbound Planets Roam the Milky Way?

Life as we know it exists on a cozy planet in a stable orbit around a sun shining brightly in its sky. But a new study hints that the most common life in the universe might exist deep inside eternal-night worlds far from any star, adrift in the icy dark of interstellar space.

Free-floating planet
The Milky Way likely hosts billions, and possibly trillions, of unbound planets, some of which may have atmospheres thick enough to support bacterial life. Loose planets may even outnumber stars in the galaxy, but a more precise count awaits future telescopes such as WFIRST and LSST.
Caltech / NASA
Researchers at the Kavli Institute for Particle Astrophysics and Cosmology (KIPAC) at Stanford University estimate that "nomad" planets, ejected from their home stellar system and now free-floating through the Milky Way, could outnumber stars by as many as 100,000 to 1. Earlier estimates were more like a handful to 1, though previous studies have only counted unbound planets more massive than Jupiter.


Glenn A. Walsh, Project Director,
Friends of the Zeiss < >
Electronic Mail - < >
  < >
Twitter: < >
Facebook: < >
Blog: < >
Author of History Web Sites on the Internet --
* Buhl Planetarium, Pittsburgh:
  < >
* Adler Planetarium, Chicago:
  < >
* Astronomer, Educator, Optician John A. Brashear:
  < >
* Andrew Carnegie & Carnegie Libraries:
  < >
* Civil War Museum of Andrew Carnegie Free Library:
  < >
* Duquesne Incline cable-car railway, Pittsburgh:
  < >
* Public Transit:
  < >

No comments:

Post a Comment