#ThisDayinHistory: Astronomers host 1st-ever comet livestream from Chile
On September 2, 2025, astronomers at Gemini South Observatory in Chile hosted a live event to watch interstellar comet 3I/ATLAS—an actual visitor from beyond our solar system, discovered just two months ago.
Using advanced tools like GMOS and GHOST, scientists got a rare chance to study what this cosmic traveler is made of as part of the Shadow the Scientists initiative.
Comet's tail and nucleus were visible during the event
Early looks with Hubble and James Webb showed that 3I/ATLAS has a tiny nucleus (under 2.99km wide) and is unusually rich in carbon dioxide.
During the livestream, viewers caught its faint glow and growing tail—classic signs it's waking up as it nears the Sun.
Scientists are excited to keep tracking it when it pops back into view in November before heading off into deep space again.