The interstellar comet Borisov was shiny and new when it passed through our solar system

For a long time, astronomers thought our second alien interstellar visitor*, the comet 2/I Borisov, was rather boring: It looked pretty much like every small comet from our own solar system.

However, now it appears that it was special: It was pristine, almost completely unchanged since it formed, meaning ours was the first solar system it visited closely.

Isn't that nice?

Hubble Space Telescope image of the comet 2I/Borisov (formerly C/2019 Q4 (Borisov)). The blue color was added to a graysca...