Most astronomers agree there are only four terrestrial, or rocky, planets in our solar system, all of which lie close to the sun. But new research suggests that up to five more may be lurking at the outer bounds of the solar system.
Free-floating planets (FFPs) are planet-size objects that don't orbit a star. Also called rogue planets, FFPs either form from clumps of gas unconnected to any star or arise around stars but get flung out of their home orbits. The James Webb Space Telescope (JWST) has identified hundreds of rogue planets in the Milky Way and beyond, including waltzing pairs of Jupiter-size planets in the belly of the Orion constellation. Simulations show most FFPs are probably as big as Mars.
