“Nomad” planets (also called “rogue planets”) are planets that are not attached to any particular star and are not part of any particular solar system. Scientists now believe that that there are more of these heavenly bodies in the Milky Way Galaxy than originally believed. In fact, there could be up to 100,000 times more of these nomad planets than there are stars in the Milky Way – a staggering number considering the number of stars in the Milky Way.
Nomad planets are detected by a process known as gravitational microlensing, which has to do with how a large object passes in front of a star.
Most planets in the Milky Way Galaxy are theorized to have host stars, and it is thought that at least some of the nomad planets were once part of a solar system, but were “pushed out”. But scientists now believe that there is evidence that some of them were not ever part of any system. Scientists have known for some time now that there was a lot of “junk” floating around in the Milky Way, but now much of this “junk” can be categorized.
Planets that are attached to a star via a solar system benefit from the heat generated from that star, but nomad planets do not enjoy this benefit. Scientists are theorizing that these rogue bodies may be able to generate their own heat through tectonic activity or via internal radioactive decay.
What this all means is that all of the theories regarding the formation of planets may have to be re-examined. In fact, Alan Boss of the Carnegie Institution for Science has been quoted as saying “We are not in Kansas anymore, and in fact we never were in Kansas.”
Some of these bodies may be asteroid-like rock bodies with characteristics like Pluto, while others may be gas giants like Jupiter. Some may even be solid objects with dense atmospheres. Moreover, it is within the realm of possibility that many nomad planets could have moons with their own ecosystems.
Interstellar objects such as nomad planets may seem on the surface that the existence of life on these bodies would seem unlikely, but scientists theorize that if the planet has a thick atmosphere, anything is possible especially microbial life.
Currently, scientists have discovered more than 500 planet-like objects outside our solar system – most of them attached to a star. But they have also discovered about a dozen of them that do not seem to be attached to a nearby star.
However, to be sure, this data needs to be confirmed – and that could take years or even decades. NASA has proposed building a spacecraft that could help with this confirmation.
