Astronomers from the OGLE (Optical Gravitational Lensing Experiment) project have discovered a Mars- to Earth-mass free-floating, or rogue, planet through a technique called gravitational microlensing. Gravitational microlensing is a technique that facilitates the discovery of distant objects by using background stars as flashlights. When a star crosses precisely in front of a bright star in … Continue reading Astronomers Discover Smallest Free-Floating Exoplanet Yet