The NASA/ESA Hubble Space Telescope has made two new observations of Comet 2I/Borisov – only the second interstellar object known to have passed through our Solar System, and one of the fastest comets, moving at a cool 175,000 kilometres an hour.
In the image on the left, Borisov appears in front of a distant background spiral galaxy. The galaxy’s bright central core appears smeared because Hubble was tracking the comet. Borisov was approximately 326 million kilometres from Earth in this exposure. Its tail of ejected dust streaks off to the upper right.
The image on the right was taken shortly after the comet’s closest approach to the Sun. It = is 298 million kilometres from Earth in this photo, near the inner edge of the asteroid belt. The nucleus, an agglomeration of ices and dust, is still too small to be resolved. The bright central portion is a coma made up of dust leaving the surface.