Interstellar comet 3I/ATLAS, only the third confirmed interstellar object seen entering our solar system, makes its closest approach to Earth overnight Dec. 18–19. Skywatchers can follow along even without a telescope using online trackers and live views, turning the flyby into a shared, low-stress stargazing moment. Scientists are also using a fleet of space-based instruments to learn what the comet is made of and how it behaves as it heads back out toward interstellar space.

Highlights:

• Exact flyby time: NASA’s Jet Propulsion Laboratory published a pinpointed closest-approach time for Dec. 19, helping observers plan when to look.
• X-ray tail physics: Two space telescopes detected an X-ray glow extending about 250,000 miles (400,000 km), produced as gases from the comet interact with charged particles streaming from the sun.
• Clipper’s UV window: Europa Clipper’s Ultraviolet Spectrograph observed 3I/ATLAS for about seven hours, capturing ultraviolet data during a period when Mars- and Earth-based observing was difficult or impossible.
• Easy tracking options: Observers can track 3I/ATLAS without a telescope using app-based sky maps and web tools, plus follow online imagery as it recedes from the sun on its way out of the solar system.
• Why some are intrigued: Separate commentary has highlighted a set of “anomalies” and urged attention to unexpected aspects of 3I/ATLAS, reflecting an active—if not universally shared—interest in scrutinizing the visitor closely.

Perspectives:

• NASA/Europa Clipper teams: Ultraviolet measurements from Europa Clipper provided a rare viewing geometry and filled observational gaps when ground/Mars-based viewing was impractical, adding useful composition and activity data. (Phys.org)
• Space-telescope researchers: The X-ray detection is presented as evidence of solar-wind interaction with the comet’s released gases, offering a way to probe how an interstellar comet behaves in the inner solar system. (Space.com)
• Public skywatching guides: Outlets emphasize accessibility: people can follow the flyby through trackers, online streams, and simple observing plans even without specialized equipment. (Space.com)
• Independent commentary (Avi Loeb): Commentary argues the object shows multiple unusual features that were not forecast and says researchers should pay attention to those details. (Google News aggregation)

Sources:

• Latest Comet 3I/ATLAS news: Comet close approach today - Space - google.com
• 4 ways to track 3I/ATLAS without a telescope as it makes its closest approach to Earth tonight - space.com
• Comet 3I/ATLAS: Europa Clipper captures rare ultraviolet view - phys.org
• Comet 3I/ATLAS reaches its closest point to Earth tonight: How to see it in the sky and online - livescience.com
• Europa Clipper Captures Unique View of 3I/ATLAS - sci.news