Weighing Rogue Planets Enables Population Estimates

Using simultaneous ground‑ and space‑based microlensing (Gaia plus Earth telescopes) to measure a lens’ mass breaks a decades‑old observational barrier: it converts single microlensing flickers from ambiguous detections into objects with known masses and distances. That methodological advance makes it possible, for the first time, to move from anecdotal rogue‑planet sightings to statistically constrained population estimates and to discriminate formation scenarios (ejection from systems vs. failed star formation). — If this technique is scalable it will let astronomers quantify how many free‑floating planets the galaxy contains, reshaping theories of planet formation, informing telescope targeting priorities, and affecting astrobiology and public interest in interstellar objects.