Comete interstellaire 2I/Borisov
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 Space Telescope images.
On the left, a distant background galaxy near the line-of-sight to
Borisov is blurred as
Hubble tracked the speeding comet and dust tail about
327 million kilometers from Earth.
At right, 2I/Borisov appears shortly after perihelion, its closest
approach to Sun.
Borisov's closest
approach to our fair planet, a distance of about 290 million
kilometers, will come on December 28.
Even though Hubble's sharp images don't resolve the comet's nucleus,
they do lead to estimates of less than 1 kilometer for its diameter.