Comet 3I/ATLAS, the third interstellar object ever detected, reached its closest point to Earth overnight from Thursday to Friday (Dec. 18 to 19), and it remains in a good viewing position tonight.

While Comet C/2025 R2 (SWAN) made its closest pass to Earth on October 20, 2025, at a distance of approximately 39.1 million kilometers (0.26 AU), it remains a visible, albeit challenging, target for ...