Interstellar Comet 3I/ATLAS Reveals Unusual Composition and Ancient Origins
Astronomers are studying interstellar comet 3I/ATLAS, which exhibits a high carbon dioxide content and may be one of the oldest objects observed in our solar system.
Astronomers are closely observing 3I/ATLAS, the third known interstellar object to traverse our solar system. Detected on July 1, 2025, by the Asteroid Terrestrial-impact Last Alert System (ATLAS) in Chile, the comet is traveling at approximately 130,000 miles per hour and is expected to reach its closest point to the Sun on October 30.
Recent observations using the James Webb Space Telescope's Near-Infrared Spectrograph have revealed that 3I/ATLAS's coma contains eight times more carbon dioxide than water vapor, a composition markedly different from typical solar system comets.
The comet's trajectory suggests it originated from the Milky Way's thick disk, a region known for its older stars. This implies that 3I/ATLAS could be over 7 billion years old, potentially making it the oldest comet ever observed.
As 3I/ATLAS approaches the Sun, its activity is increasing, with a growing tail and expanding coma. Despite its proximity, the comet poses no threat to Earth, as it will remain at least 150 million miles away during its passage.
Astronomers are utilizing various telescopes, including the Vera C. Rubin Observatory and the James Webb Space Telescope, to study 3I/ATLAS. This rare opportunity allows scientists to analyze material from another star system and gain insights into the formation of exoplanets.