Interstellar Comet 3I/ATLAS Passes Solar System Near Mars Revealing Unusual Composition

The interstellar comet 3I/ATLAS, first detected in July 2025, continues to captivate astronomers with its unusual characteristics as it travels through our solar system. Observations from NASA's James Webb Space Telescope reveal that its coma is dominated by carbon dioxide rather than water, suggesting it may have formed in a high-radiation environment or near the CO2 ice line of its parent star’s protoplanetary disk. NASA’s SPHEREx and Hubble telescopes have also studied 3I/ATLAS, providing insights into its composition and size, with no threat posed to Earth. While initial size estimates suggested the comet might be up to 20 kilometers wide, more recent assessments indicate it is likely around 5.6 kilometers, but still large enough to cause catastrophic effects if it were to impact a planet. The comet will pass close to Mars at about 0.19 AU in early October 2025, raising some public concern, although scientists maintain confidence in its safe trajectory. Additionally, Harvard astrophysicist Avi Loeb has proposed a controversial theory that 3I/ATLAS might be emitting its own light and could possibly be a spacecraft powered by nuclear energy, though this hypothesis requires further verification.