Comet 3I/ATLAS reaches perihelion, begins solar transit

Image: This is a Hubble Space Telescope image of the interstellar comet 3I/ATLAS. Hubble photographed the comet on July 21, 2025, when the comet was 277 million miles from Earth. Image credit: NASA, ESA, David Jewitt (UCLA); Image Processing: Joseph DePasquale (STScI). Article by  Brooks Mendenhall. Astronomy – October 30, 2025.

Key Takeaways

• Interstellar Comet 3I/ATLAS will reach perihelion, its closest approach to the Sun, on October 30, 2025, marking the climax of its brief, hyperbolic trajectory through our solar system before its permanent departure.
• A surprising detection of water vapor, identified by its hydroxyl byproduct, was made by NASA’s Neil Gehrels Swift Observatory when the comet was at a distance from the Sun usually insufficient for such activity. […]

Click here to view original web page at www.astronomy.com