Scientists have discovered what they say could be the smallest free-floating planet ever detected. The planet was discovered by University of Warsaw researchers in the middle of the Milky Way, and is estimated to be between the size of Earth and Mars.
Free-floating or “rogue” planets don’t orbit stars, and are notoriously difficult to detect. The researchers used a technique called “microlensing,” which allows scientists to find planets they wouldn’t otherwise be able to observe. “Rogue planets don't orbit stars, they are gravitationally unattached to any host star. They don't emit any visible radiation, so they cannot be detected using traditional astrophysical techniques,” Przemek Mroz, one of the co-author’s of the paper explained on Twitter.