星际空间来的博里索夫彗星
2019 December 14 Interstellar Comet 2I/Borisov Image Credit: NASA, ESA, and D. Jewitt (UCLA) et al. Explanation: From somewhere else in the Milky Way galaxy, Comet 2I/Borisov is just visiting the Solar System. Discovered by Crimean amateur astronomer Gennady Borisov on August 30, 2019, the first known interstellar comet is captured in these two recent Hubble...