What Is Comet Lemmon and Why It’s Newsworthy Comet Lemmon, officially designated C/2025 A6 (Lemmon) and also known as comet A6, is a long‑period visitor from the outer edges of the solar system. First discovered on Jan. 3, 2025 by the Mount Lemmon Survey near Tucson, Arizona, this icy wanderer is making a rare, once‑in‑1,350‑year…