Comet 3I/ATLAS: A 7 Billion-Year-old Solar System Oddity
Discovered in July 2025 by astronomers Origin from Milky Way's thick disk Estimated age of 7 billion years Nucleus under 5.5 km in size Large bright coma observed Carbon dioxide to water ratio 8:1 Ratio 16x higher than typical comets Formed near carbon dioxide ice line Observed with James Webb Space Telescope and Hubble Space Telescope.