Mystery Interstellar Object Might Be Oldest Known Comet

Astronomers studying 3I/ATLAS—only the third interstellar object ever detected—say it may have originated in the Milky Way’s ancient “thick disk” region. With a two-thirds probability of being over 7 billion years old, it could be the oldest comet ever observed. As it approaches the Sun, its ice-rich nucleus is already showing signs of developing a coma and tail.