APOD: 2022 March 5 - Interstellar Comet 2I Borisov

Good morning, Rallypoint, and welcome to the March 5th Astronomy Picture of the Day (APOD): "Interstellar Comet 2I Borisov." I had forgotten this story from 2019, so it may bear repeating for someone else. The comet was discovered by the Crimean amateur astronomer and telescope maker Gennadiy Borisov on August 30, 2019. Based on its orbital characteristics, scientists believe that 2I Borisov is a true interstellar (e.g. from another solar system) visitor. The comet passed through the ecliptic of the Solar System at the end of October 2019, and made its closest approach to the Sun on December 8, 2019.

Both images are from the Hubble Space Telescope (HST). On the left, inbound 2I Borisov is framed by a distant background galaxy. On the right is 2I Borisov shortly after its closest approach to the Sun. The comet was closest to Earth ( 290,000,000 km/181,250,000 mi) on December 28, 2019.