Illustration of Comet Bernadinelli-Berstein. Image credit: NOIRLab/NSF/AURA/J. da Silva

In late June an interesting object was discovered heading inwards from the outer solar system, identified in archival images from a survey of the sky. It was initially thought to be worth keeping an eye on over the next decade or so, as it approaches the orbit of Saturn before heading back out to the outer reaches – a chance to keep an eye on a distant wanderer.

Further observations have shown that 2014 UN271 (its official designation) appears to be active, with a coma and tail like a comet – unusual for an object so far from the Sun. If it is a comet, becoming Comet Bernadinelli-Bernstein, it could be the largest on record, possibly more than 100km across. This month Dr Meg Schwamb, from Queens University Belfast, explains where this objects fits in terms of the size and scale of the Solar System, while Dr Tim Lister, from Las Cumbres Observatory, explains what he and colleagues have found from those early follow-up observations.

Find out what to expect over the next decade from this icy visitor, and how future telescopes should help us find out quite how unusual it is.