There may be 100,000 times more wandering “nomad planets” in the Milky Way than stars, and some may carry bacterial life, according to a new study by researchers at the Kavli Institute for Particle Astrophysics and Cosmology (KIPAC).

If any of these nomad planets are big enough to have a thick atmosphere, they could have trapped enough heat for bacterial life to exist,” said Louis Strigari, leader of the team that reported the result in a paper submitted to the Monthly Notices of the Royal Astronomical Society.

Last year, researchers detected about a dozen nomad planets, using a technique called gravitational microlensing.

A confirmation of the estimate could lend credence to another possibility mentioned in the paper — that as nomad planets roam their starry pastures, collisions could scatter their microbial flocks to seed life elsewhere.

KIPAC is a joint institute of Stanford University and the SLAC National Accelerator Laboratory.

Ref.: Louis E. Strigari, et al., Nomads of the Galaxy, 12 Jan 2012, ArXiv, http://arxiv.org/abs/1201.2687

Ref.: Jack Singal, Nomadic Planets May Swarm the Galaxy, Tidbits from 2012, Kavli Institute for Particle Astrophysics and Cosmology, 22 Feb 2012.