# Astronomers may have discovered the first exomoon Giant satellite found outside our Solar System - **Source:** [Hacker News](https://news.ycombinator.com) - **Published:** 2026-07-23 - **Topic:** [Business](https://brifing.si/c/business) - **Original article:** - **On Brifing:** https://brifing.si/s/051fd67b-90b8-4efd-adc1-80813211f1ba ## Historic discovery ESO's Very Large Telescope has detected a moon-like object outside our Solar System for the first time. This massive celestial body in the CD-35 2722 system challenges traditional definitions of 'planet' and 'moon'. ## System's unusual structure The discovered exomoon orbits a brown dwarf. The largest object in the system is the star CD-35 2722, with about half the Sun's mass. This triple configuration is making astronomers rethink classification systems. ## Classification challenge The object, larger than Jupiter, is technically planet-sized but orbits a brown dwarf instead of a star. Researchers call it an 'exosatellite', though it doesn't fit traditional moon definitions. ## Discovery method The team applied the radial velocity method used to find the first exoplanet around a Sun-like star. Using the CRIRES+ instrument, they measured small wobbles in the brown dwarf to detect this giant satellite. ## Scientific excitement Findings published in Nature have generated significant interest. Alice Zurlo calls this discovery 'truly a breakthrough' that will help us understand cosmic diversity. ## Previous research Despite over 6000 exoplanets discovered to date, no confirmed exomoon had been found. Only a few candidates were spotted with limited evidence. ## System's uniqueness Lead author Kevin Hoy describes the system as 'super weird'. The brown dwarf's 30 Jupiter masses and the satellite's enormous size challenge formation theories. ## Terminology debate Astronomers emphasize the need for new terminology. Traditional 'planet', 'star' and 'moon' definitions prove inadequate for describing extrasolar diversity. ## Future research ESO's upcoming Extremely Large Telescope (ELT) will detect smaller exomoons. Its 39-meter mirror will help astronomers better understand cosmic object diversity. ## Impact on formation theories This discovery offers opportunities to test theories about celestial object formation. How giant satellites form and maintain orbits around brown dwarfs remains a major question. ## International collaboration The discovery involving researchers from Chile, Germany, Italy and the US highlights the importance of global cooperation in astronomy. ESO's infrastructure enables such groundbreaking findings. ## New era in astronomy This discovery opens a new chapter in our cosmic understanding. Extrasolar diversity makes us question how special or ordinary our own cosmic neighborhood might be. ## Sources covering this story - https://www.eso.org/public/news/eso2610/ — --- _Summary written by Brifing from the original reporting. Copyright in the original article belongs to its publisher; read the full piece at the link above._