A nomad planet is a rogue planet floating through space, rather than being locked in orbit around a star. In 2000, a group of Spanish astronomers reported planets up to 15 times the size of Jupiter in Orion. In 2011, astronomers reported 10 planets, around the size of Jupiter, mostly consisting of nomad planets. Recent studies by a joint institute between Stanford Universtiy and SLAC National Accelerator Laboratory, called Kavli Institute for Particle Astrophysics and Cosmology (KIPAC), show there could possibly be an estimate of 100,000 times more nomad planets in the Milky Way, than stars.
“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.
This new study could show possibility of life on other planets. Most of the characteristics of these wandering planets are unknown. Without a sun to provide warmth, there is still a possibility that heat could be generated from internal radioactive decay, or tectonic activity.
“To paraphrase Dorothy from ‘The Wizard of Oz,’ if correct, this extrapolation implies that we are not in Kansas anymore, and in fact we never were in Kansas,” Alan Boss, of the Carnegie Institution for Science in Washington, D.C., said in a statement. “The universe is riddled with unseen planetary-mass objects that we are just now able to detect.”
KIPAC used gravitational microlensing to detect such planets. It examines the effects of massive objects passing in front of stars. No one is sure how the masses form, but some were likely ejected from other solar systems. Researchers based the estimate on the amount of visible matter in the galaxy and how much existing chemical elements from which the universe evolved almost 14 billion years ago. These elements provide the base for other elements, such as gases, ice, and rock, that make up planets.
In the early 2020s, the Wide Field Infrared Survey Telescope (WFIRST) (space-based), and the Large Synoptic Survey Telescope (ground-based), both next generation telescopes, are to begin operations to attempt to produce more detailed observations. WFIRST is most likely going to count these nomad planets.
“Few areas of science have excited as much popular and professional interest in recent times as the prevalence of life in the universe. What is wonderful is that we can now start to address this question quantitatively by seeking more of these erstwhile planets and asteroids wandering through interstellar space, and then speculate about hitchhiking bugs” said study co-author Roger Blandford, director of KIPAC, in a statement.
