What caused that hole? The hole in question appears as a small dark circle on the far right. If the above image of aerogel seems dull and uninteresting, then welcome to one aspect of real world science.

Heading for its closest approach to the Sun, or perihelion, on December 19 comet C/2017 K2 (PanSTARRS) remains a sight for telescopic observers as it sweeps through planet Earth's skies in the constellation Scorpius.