Jupiter-sized “planets” free-floating in space, unconnected to any star, have been spotted by the James Webb Space Telescope (JWST).
3 points
My knowledge of astrophysics is nearly null but my guess would be based on its size and hypothetical mass scientists would know how massive a celestial body would have to be in order for the rogue planets to be trapped by its gravity and if there aren’t any bodies of that size in the vicinity then they can conclude they are rogue.
I could be 100% wrong though.
