A newly found world blurs the boundary between planet and moon

Astronomers have discovered a cosmic object that defies easy classification — it's Jupiter-sized, orbits a brown dwarf, which itself orbits a small star, making it the first known "exosatellite." Researchers coined that term because existing words like "exoplanet" and "exomoon" don't quite fit. The find reignites debate about whether a planet is defined by its physical properties or its orbital relationship to other bodies.