Arrokoth

Following its flyby of Pluto, the New Horizons spacecraft was tasked with a new mission: to visit another distant object in our Solar System (which happened to be located close to New Horizon's post-Pluto flight path). This composite image of the primordial contact binary Kuiper Belt Object 486958 2014 MU69 was compiled from data obtained by NASA's New Horizons spacecraft as it flew by the object on 1 January 2019. The image combines enhanced color data (close to what the human eye would see) with detailed high-resolution panchromatic pictures.

This object was originally nicknamed Ultima Thule, a Latin phrase meaning "beyond the borders of the known world". In 2019 it was officially named Arrokoth, the Powhatan word for "sky". Arrokoth is the most distant and most primitive object yet visited in our Solar System. It orbits at a distance of 44.5 AU from the Sun, with an orbital period of 298 years. The object is approximately 35 km across in the long direction. Its reddish color comes from a surface coating of naturally occurring organic molecules.

The lobes of Arrokoth are flattened (not spherical).

The complex geology of Arrokoth, with the nucleus of comet 67P to scale. Notable surface features are highlighted. The eight subunits of the larger lobe, labeled ma to mh, are rolling topography units that might be "building blocks" of the larger lobe.

Arrokoth likely used to be two separate objects. It probably formed over time as a rotating cloud of small, icy bodies started to combine. Eventually, two larger bodies remained and slowly spiraled closer until they touched, forming the bi-lobed object we see today.