Rogue planets may be more numerous than stars
If you look at a picture of space, you would assume that the many specks of light you see are stars. While it is true that there are trillions upon trillions of them all over the universe, there is a recent theory that suggests free-floating or rogue planets actually outnumber them.
The strangest thing is that they do not seem to have a host planetary system. The theory is that they were either never gravitationally bound by a star or that they were ejected from the system they were formed in. Some researchers have estimated that the Milky Way has almost two rogue planets for every star.